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FORCinel

FORCinel v. 2.0: A whole new way to create FORC diagrams!

 

FORCinel is a free software package for the processing and analysis of First Order Reversal Curve (FORC) diagrams. The software is written using Igor Pro by Wavemetrics. Although Igor Pro is a commercial package, Wavemetrics offer a fully functional demo version for both Mac and Windows, so you can download it and get started right away! The full version of Igor Pro is available to students at a heavily discounted price.

 

Version 2.0 is a major new version of FORCinel that incorporates several recent advances in FORC analysis. See What’s New in Version 2 to find out more!

 

FORCinel is written by Richard Harrison of the Department of Earth Sciences, University of Cambridge. Please feel free to contact the author with any questions/bug reports/feature requests.

 

You can use FORCinel for free, but please cite the following reference in any scientific publications that use FORCinel output:

 

Harrison,R. J., and J. M. Feinberg (2008), FORCinel: An improved algorithm for calculating first-order reversal curve distributions using locallyweighted regression smoothing, Geochem. Geophys. Geosyst., 9, Q05016,doi:10.1029/2008GC001987.

 

To get started, go to the Download page. Good luck!

 

73 Responses to FORCinel

  1. Richard Harrison says:

    Please feel free to post comments and questions here about FORCinel and I’ll do my best to address them!

    Richard

  2. Maricel says:

    Hello, I’m a physics from Argentina.
    I want to know how do you make the data input. I use a magnetometer SQUID and I need process the data before I do the FORCs curves. Are there any tutorial for prepare the data input?
    Thank you,
    Regards
    Maricel

    • Richard Harrison says:

      Hi there (and congrats for being the first poster…),

      A good question. FORCinel is designed to read in files generated by Princeton Measurements Corp. VSM and AGM systems. The Princeton systems have been the defacto standard for FORC acquisition in the rock magnetism community for many years (they are now owned by Lakeshore). However, FORC data can indeed be measured on other systems. The only way to read in data from other systems at the minute is to convert your data into a replica of a standard Princeton text file. Open up the bush.txt test data file in a text editor. You will see some header information, which you should copy exactly and replace the key parameters with appropriate values according to your particular data. Let me know if you are unsure of what the parameters mean, but mostly they are self explanatory if you know the details of the FORC acquisition process. After that you will see the measurements (field, moment, temperature). The first line of data is the first drift field measurement. The next line is the 1st FORC curve (which has just one point in it). Each FORC curve is followed by a drift measurement. Basically you need to arrange your data in exactly this format and it should be possible to read it in. It is critical, however, that you do the measurement according to the official FORC protocol, otherwise the processing may not work as expected.

      I know several users who have done this successfully. If anyone out there has written a script to do this then let me know! Get in touch if you need more detailed instructions/advice.

      Rich

    • Richard Harrison says:

      Hi again,

      This reminds me, a user did send me a while back a script to generate Princeton files from data collected on a standard VSM. I’ve never tried to use it myself, but I’d be happy to send it to you and/or put you in touch with the person that wrote it.

      Cheers

      Rich

      • Maricel says:

        Thank you! I wrote most of the data like the file “bush” (the program make the curve m vs H). But the program can not make the curve forc, he tells me: “you must have at least as many data points as fit parametres”.So I suposse the program is not reading well the data input of the “Ha”. I’ll fix the data so that it can be read by the program (our protocol is different from that measured in the “bush” text).
        Please send me the script for generate the file input, it will very helpful.
        Regards,
        Maricel

        • Richard Harrison says:

          I have forwarded you a message and program via email. Please contact the original author with any questions. I can take a look at your raw data myself to see if it is suitable for FORC analysis.

          Cheers

          Rich

      • ana cabanas says:

        Hi Rich,

        I’m a phd student from Spain. I’m trying to convert a file from my VSM in a replica of the Princeton one but I have some doubts about the parameters I have to chande, do you have this script to generate the Princeton file? or could you explain what is the meaning of the following?
        Hb1
        Hb2
        Hc1
        Hc2
        HCal
        HNcr

        NCrv
        PauseCal
        PauseNtl
        PauseSat
        SlewRate

        Field range
        Moment range

        Orientation
        Elapsed time
        Slope corr.
        Saturation

        Many thanks in advance!

        • Richard Harrison says:

          Hi

          I don’t have a script myself, but other users may have one that they could share. One day I will try and write one myself…

          Some of the parameters you list are not important and can be left at their default values (e.g. see the Bush.txt example file). Other are important:

          Hb1: The upper value of the range of interaction field (Hu) values in the final FORC diagram
          Hb2: The lower value of the range of interaction field (Hu) values in the final FORC diagram
          Hc1: The lower value of the range of coercivity (Hc) values in the final FORC diagram (usually set to 0)
          Hc2: The maximum value of the range of coercivity (Hc) values in the final FORC diagram
          HCal: The field used to make the drift measurements in between each FORC measurement
          HNcr: Not read in, leave at the default value
          NCrv: The total number of FORC curves measured
          PauseCal, PauseNtl, PauseSat, SlewRate: these are pause times and the rate of field change during measurement. These are used as part of the drift correction procedure. If you are not performing drift measurements on your VSM then leave these at their default values and fill the data file with fake drift measurements in between each FORC curve.

          Field range, Moment range, Orientation, Elapsed time, Slope corr., Saturation: None of these are used, so leave at their generic values.

          Hope that helps

          Rich

  3. Himmat Singh says:

    Hello Richard,
    I am working on ferroelectric ceramic materials. I want to use this tool for the analysis of ferroelectric hysteresis loops. I have only P and E values. How can i make a input file for the FORC analysis.

    • Richard Harrison says:

      Hi there,

      I have often wondered whether FORC analysis could be applied to ferroelectric materials. I am not so familiar with how flexible the measurement systems are for ferroelectrics, but in principle there is no reason why FORCinel cannot be used to analyse FORC data for ferroelectrics, as long as the measurement has been performed according to the correct protocol. I recommend you read the original FORCinel paper (and references therein), which has a diagram showing how the measurements should be performed. It is essential that the measurements are made on a square grid of points in Ha-Hb space (as shown in Fig. 1 of the FORCinel paper) and that the sample is saturated inbetween the measurement of each FORC curve. The data should be placed in a text file that replicates the standard Princeton format (examine the bush.txt test data file to see this). If you look at the data in there you will see a drift measurement at a fixed field, followed by a string of datapoints for the FORC curve.

      The key question is whether your instrument is able to make measurements according to the strict FORC protocol?

      Rich

      • Himmat Singh says:

        Sir,
        Thanks for your reply. There are many papers on FORC analysis for ferroelectric hysteresis loops. From my instrument I can get hysteresis loop in a range of applied field and temperature. Many of the papers just representing the FORC curves for the hysteresis loop under variable applied field. What are the three rows of data in the bush.txt file. Is it important to mention complete header information.

        • Richard Harrison says:

          Hi,

          The three columns are field, moment, temperature (or in your case E, P, T). It is important to have the header information, although not all parameters are read in. The key ones are the following (the load will fail if these are not present):

          Units (cgs or SI/Hybrid)
          Averaging time (time taken for each measurement point)
          hb1 (lower value of interaction field range)
          hb2 (upper value of interaction field range)
          hc2 (upper coercivity value)
          hcal (field value used for drift measurement)
          hsat (field used to saturate sample between forc curves)
          ncrv (number of forc curves measured)
          pausecal (pause time before making drift measurement)
          pausentl (pause time at the reversal field before starting each forc curve)
          pausesat (pause time at the saturation field)
          slewrate (rate of change of field during forc measurement)
          smoothing (smoothing factor – any number will do)
          Ndata (number of data points, the number is not important but this line is used to detect the beginning of the data stream so must be present).

          After Ndata there should be a blank line and then the data should start, beginning with the first drift measurement, then the first forc curve (with just one point in it). Then alternate between drift measurement and forc curve with blank lines separating each. As long as the forc measurements are on a square grid, things should work as normal after that.

          The timing and rate information is only used in the drift correction routine. If you are not performing a drift correction then the actual values used for these are not important.

          If you have trouble, send me some of your data and I can take a look.

          Rich

  4. fatima martin says:

    Dear Richard,

    Thank you very much for the new version, which I have quickly tested. However I have not been able to run the software while using a Macbook I get a message “this is a demo version” in a pop-up window that does not disappear.

    Could you help me with that?

    Fátima

    • Richard Harrison says:

      Hi

      I guess you are running the demo version of Igor? Check you have the latest version of Igor downloaded. There is usually a 30 day free trial, after which you can still use the software in demo mode but are no longer able to save anything. There is usually a button on the pop up that you press to continue to use Igor in demo mode after your 30 days have expired.

      Cheers

      Rich

  5. Richard Harrison says:

    Dear Users

    I found a bug in the ‘Load FORCs new format’, which was related to Princeton deciding to use a different name for a key variable in newer versions of their software. Hopefully this is now fixed so please download the latest version from our Download page.

    Cheers

    Rich

  6. Richard Harrison says:

    Dear all,

    A new minor update to FORCinel is now online (2.01). This had just one added feature: VARIFORC now remembers the last VARIFORC smoothing parameters used, so the next time you go to change the smoothing factor, the previous parameters are already entered into the dialogue box. This makes it much easier to test different smoothing parameters and get the best values for your data. The values are stored in the wave “last_sf_used” if you need to see them at any time.

    Cheers

    Richard

  7. Richard Harrison says:

    A new version of FORCinel (2.02) has now been uploaded. This version includes significant improvements to the user interface of FORCinel and a much more streamlined workflow for loading and processing FORC diagrams, as well introducing some major new features such as the new “Extract Central Ridge” feature. Go to the download page to download the latest version.

  8. Cristian Necula says:

    Dear Richard,

    I am Cristian Necula, University of Bucharest, Romania (the one with with the bug in the ‘Load FORCs new format’ few lines above). I have a problem with FORCinel. I downloaded the new version (2.02) and tried to load a FORC. But pressing ‘Load FORC file’ the program is closing. I tried the 2.0 version too and when press ‘Load FORCs new format’ the program is closing again. The funny thing is that two weeks ago it worked perfectly (2.0 version). I did not change anything in my computer since then (I work on a Windows 7 platform). Please could you help me?

    Thank you so much,
    Cristian

  9. Richard Harrison says:

    Hi Cristian

    I have just downloaded it myself and it works no problem. I am on a mac, however. What version of Igor are you using?

    Rich

    • Cristian Necula says:

      Dear Richard,

      I’m using Igor 6.11 version. But two weeks ago it worked (FORCinel 2.0 version). I made several FORC analysis using VARIFORC. Now it closes when I want to load a FORC. And I do not understand why.

      Thanks,
      Cristian

  10. Dear Richar,
    I’ve just started working with FORCs, and I’d like to know if there is an option to automatically stack different data sets to create a single FORC

    Thank you
    Daniel

    • Richard Harrison says:

      Hi there

      This is one of the next features I will build in. I have produced a version for individuals that can load, process and average multiple FORCs in the past. I will dig this out and send you a copy while I work on building it into the next version. Send me an email and I will discuss it with you!

      Cheers

      Rich

  11. Rajan says:

    Hi Richard,
    I am new to FORC analysis. I read the above FAQ and came to know that the collected VSM data has to be rearranged in the format of Princeton files. Could you please send me the script to generate Princeton files from data collected on a standard VSM.

    Thank you.

  12. Rajan says:

    Dear Richard,
    I am a research scholar in India. I just started using FORC analysis. I have collection of M(H) with different Ha values from VSM measurement (LakeShore instr.). I got struck while creating the bush.txt file with the specified format. However, I read these FAQ and found that you mentioned about the program which used to generate Princeton files from data collected on a standard VSM. Is this program might help me to build an FORC analysis or what to be done?

    Thanks & regards
    Rajan…

    • Richard Harrison says:

      Hi

      Someone did write a converter once, but I have never tested it as it is for PC. It should not be too difficult to do – you just need to copy the header information and replace the key variables with your values. When you get to the actual measurements, the key is to always alternate between a single drift measurement, followed by the FORC measurement. If you have not performed drift measurements, then just use dummy values for these. Feel free to email me directly if you have specific questions.

      Cheers

      Rich

  13. Charbel A says:

    Dear Richard,
    I am a physicist doing my post doc in France.
    First of all thanks a lot for this useful program.
    May I have by email an exemple of a .txt data file for a FORC measurement?
    I would like to know how to organize the minor loop data inside the file (column, rows, field, magnetization…).
    Thanks a lot,
    Charbel

    • Richard Harrison says:

      Hi there,

      Have a look at the bush.txt file that is provided in the download package. I can explain how the format is arranged, but it is probably best to do this via direct email. Feel free to email me directly if you have any specific questions about the contents of the file.

      Rich

  14. Please advise: trying to work on a reproduced “bush”-like .txt file I get the following errors

    while loading
    “expected wave name”, but the data are plotted correctly

    while producing forcs
    “attempt to operate on a null (missing) wave”

    Thanks in advance!

    • Richard Harrison says:

      Can you email a copy of your text file and I can have a look to see where you (or I) have gone wrong?

      Cheers

      Rich

    • Nengjun Yu says:

      Hi Panagiotopoulos,
      I am a student from China, majored in magnetism. I have the same problem with you when dealing with the FORC data. Have this problem been solved after you connected to Dr. Richard? It will great help if you can give me some advices. Thank you very much!
      Best wishes!
      Nengjun Yu

  15. Thank you very much for taking the time to go through the data file. I followed your instructions [correct delimiter errors, Use VARIFORC after FORC since the measurement points in Ha-Hb space were not equidistant ] and everything worked nicely!

    • Richard Harrison says:

      No problem, happy to help. Sorry it took me a while to get round to it. Anyway, the FORC diagram was worth it in the end – nice example of nucleation and annihilation effects!

  16. Jinhua Li says:

    Dear Richard,

    I am Jinhua Li, from Beijing, China. I try to run FOCinel v2.03 with the software Igor Pro 6.03, it does not work and shows “Procedure Scan Errow” in a small window. However, FORcine v 1.18 works. Can you please help me fix this problem?

    Thanks.
    Cheers.
    Jinhua

    • Richard Harrison says:

      Hi there,

      Usually when this happens it means you are not using the very latest version of Igor Pro. I tested FORCinel using the latest version (version 6.35). Please can you check your Igor Pro version, and let me know if there is still a problem?

      Cheers

      Rich

  17. Jinhua Li says:

    Hi Richard,

    Jinhua again. when we use the FORCine1.21 or FORCine 2.03, how to calculate the marginal coercivity?

    thanks。
    jinhua

    • Richard Harrison says:

      Hi again

      After processing the data using the Process FORCs option in the FORCinel menu, you simply have to choose the ‘Marginal Coercivity Distribution’ option in the FORCinel menu.

      If you are using VARIFORC smoothing, generating coercivity profiles it works a little differently (more flexibile but a bit more complicated). After processing using VARIFORC you should use the built in image processing features to generate coercivity distributions. This can be done by going the “Image” menu and then choosing “Image line profiles…” option. This will bring up a window that allows you to plot horizontal and vertical profiles of the FORC diagram at different positions and using different integration widths. To get the marginal distribution, choose a width that is large enough to cover all your data.

      Cheers

      Rich

  18. Eric says:

    Hi Richard,

    I’ve just begun getting into FORCs and luckily I stumbled upon this great software (I was going to do all the derivatives manually in excel before this..) but I’m having the same troubles as some of those mentioned above. We use a Lakeshore VSM (but not a PMC Micromag, just a standard VSM) and I tried to copy the data over into the bush.txt file but I definitely messed something up, i’m getting the “name already exists as a wave” error. I didn’t do drift measurements so I just inserted the dummy drift measurement from the bush.txt file in between my measurements. I believe the errors are also in part from delimiter error, but I’m not sure how to fix it. If it’s alright I would like to send you a copy of the file I’m attempting to work with.

    Thanks,
    Eric

    • Richard Harrison says:

      Hi

      Yeah, you definitely don’t want to let your FORC data anywhere near excel…

      There is usually a simple fix when people try to format the data to be compatible. Easiest if you send me an example and I will try and find the error.You’ll find my email somewhere on the website.

      Cheers

      Rich

  19. Nengjun Yu says:

    Dear Richard,
    There is no doubt that this software is great.However, I have some problems when I deal the FORC data collected from Lakershore VSM 7407. I think there are some wrong with my data format. So could you send me the standard FORC data format to me. Additionally , could you tell me the meaning of parameters that will be used in the process of the FORC diagram. The parameters I have used brfore is as follows:
    Averaging time = +1.500000E-01
    Hb1 = -1.000000E+04
    Hb2 = +1.000000E+04
    Hc1 = 0.000000E+00
    Hc2 = +2.000000E+04
    HCal = +1.845890E+03
    HNcr = +3.013702E+01
    HSat = +1.000000E+04
    NCrv = 99
    PauseCal = +1.000000E+00
    PauseNtl = +1.000000E+00
    PauseSat = +1.000000E+00
    SlewRate = +1.000000E+04
    Smoothing = 5

    Field range = +1.845890E+04
    Moment range = +2.000000E-01
    Temperature = N/A
    Orientation = N/A
    Elapsed time = +1.568249E+03
    Slope corr. = -9.189712E-07
    Saturation = N/A
    NData = 10776

    Thanks very much for help me!

    • Richard Harrison says:

      Hi

      The best thing is to send me the data you are trying to load and I will test it and find the error in your format. Can you email a test file?

      Cheers

      Rich

  20. Nengjun Yu says:

    I facing the same problems as asked:
    Please advise: trying to work on a reproduced “bush”-like .txt file I get the following errors
    while loading
    “expected wave name”, but the data are plotted correctly
    while producing forcs
    “attempt to operate on a null (missing) wave”
    Thanks in advance!

    • Richard Harrison says:

      I have looked at your data files. The problem is that your blank lines contain a tab. If you replace these with purely blank lines (just a carriage return) then it will load. Additionally I noticed that some of your data do not have commas between the numbers. I also suspect that you are not measuring your data using a standard square grid of measurement points. This means that your data will not process initially. However, if you ignore any errors and then use the VARIFORC option it should process fine, as VARIFORC first converts the data to a regular grid. You may get better results, however, if you stick to the standard FORC protocol with a regular grid of measurement points (same field step size used for reversal field and measurement field.

      Rich

      • Nengjun Yu says:

        Dear Richard,
        Thanks for your help!
        I will revised my data and try again.
        When I dealing with another data. Another problem was found. I will send the data file and the FORC diagram I got.
        Beat wishes!
        Nengjun Yu

  21. Basharat Want says:

    Thank you Prof. Richard for the useful contribution to the community. I am using Microsense EZ9 VSM for FORC data collection. After that I converted my data into bush.txt format. But still I am getting a message after Processing ” attempt to operate on a null (missing) wave”. And when I do VariForc , it displays an error message ” as many Data points and fit parameters”. Moreover the FORC diagram shows clipped distribution along horizontal direction.

    • Richard Harrison says:

      Hi

      Thanks for the message. This is a common problem when people try to convert data from non Princeton systems to use with FORCinel. One day I will try and write a more generic loader… In the mean time, if you email me directly with an example of your converted data file I can try and spot the problem with the formatting for you.

      Cheers

      Rich

  22. Dear Dr. Harrison, I have finally converted the data from MicroSense VSM to the data format accepted by FORCinel. I have a general question.
    When doing a single FORC , what is the recommended step size in going from reversal field Hr to the saturation field. Should DeltaHr be same as the step size. Actually, if step size is large, it takes less time to complete the experiment. Is there any protocol for recommended field steps and separation between two successive forcs.

    • Richard Harrison says:

      Hi

      Glad the formatting is OK now. Yes, ideally you should make sure that DeltaHr is the same as the step size – this yields a square array of measurement points, which is the usual basis for FORC measurements. FORCinel assumes that the data array is measured in this way. If your data is not evenly spaced in both measurement directions, you will get odd results, or an error when processing. You can get round this by using the VARIFORC option, which regrids unevenly spaced data into a square array. However it is better if you measure your data the correct way from the beginning.

      There is no single answer to the question “what is the recommended step size for Hr”, other than the fact it should be the same as the step size used to measure each FORC. It all depends on the range of coercivities you want to cover and the width of the features that appear in your diagram. The simplest guide is to think about the total number of FORC curves you want to measure. I recommend no fewer than 100 curves to get a good diagram, and typically people do not measure more than 600 curves. Most often a good FORC diagram is achieved with 100-300 curves. Based on this, and the range of coercivities you need to cover, you can work out what the step size should be. Usually people make a relatively low resolution measurement first, process it, and then decide whether more detail is needed in a second measurement.

      For geological samples, step sizes are typically in the range 1-10 mT. For other types of materials with higher coercivities, you may have to use higher steps.

      There is a useful discussion of step sizes and feature resolution in:

      Egli, R., A. P. Chen, M. Winklhofer, K. P. Kodama, and C.-S. Horng (2010), Detection of noninteracting single domain particles using first-order reversal curve diagrams, Geochemistry, Geophys. Geosystems, 11(1), Q01Z11, doi:10.1029/2009GC002916.

      Cheers

      Rich

      • Basharat Want says:

        Thank you Dr. Harrison for sharing your comments. It is now clear about the DeltaHr and Step size.

        • Richard Harrison says:

          Happy to help. Hope you get good data.

          Rich

          • Dear Harrison,
            I need one more expert advice on the value to be used for drift measurement. Is there any relation between the Coercivity or interaction field with the drift field to be used. Or any arbitrary value can be used for the drift measurement. I put the drift field at 0 Oersted and the FORCinel processed my data rightly. But I wonder what is the purpose of the drift measurement. If you can cite some references about drift setup.
            Regards

  23. Richard Harrison says:

    Hi

    It does not matter too much which field is used for the drift measurement – it is there so that you have a measurement at a constant chosen field in between each FORC. This allows you to see whether the response of your instrument varies during the long measurement. Based on the drift measurements, it is possible to correct for these variations. FORCinel does not apply any drift correction by default, but you can choose to apply this once the data has been loaded in (see option on FORCinel menu). My correction procedure is the same as that described by Egli in his VARIFORC paper.

    I think by default, Princeton chooses a drift measurement field that is equivalent to the highest interaction field specified, although this is somewhat arbitrary. A zero field will also work (although this does not give you the chance to see whether your applied field is drifting or not).

    Rich

  24. John McCloy says:

    Rich,
    I’m wondering if there are any plans to incorporate analysis of Extended FORCs into FORCinel. Thanks!
    John

    • Richard Harrison says:

      Hi

      Can you clarify what you mean by extended FORCs (different people have different definitions). Do you mean the option that is in the Princeton software to measure FORCs all the way to the saturation field? If so, this may already work in FORCinel. If you mean adding in missing data to overcome the issue of processing close to the Hu axis, then I have no plans to implement that yet. I have played around with the concept previously in development versions but have never been convinced that they are useful. I am always a bit reluctant to add data that does not exist – the danger is you introduce artefacts. If you can show me a good example where they make a big difference then I will certainly think about adding an option (it is not too hard to implement if I remember correctly). There are different ways to extend the FORCs into the missing data area. Which specific ones were you thinking of?

      Cheers

      Rich

    • Vincent Sokalski says:

      Hi Rich,

      First thanks for all of the effort on this software.

      I also find that I am not able to load in the “extended range” FORCS from the AGFM software. The format of the datafile seems to be significantly different than the “classic” range.

      Vincent

      • Richard Harrison says:

        Hi

        Ok can you email me an example of the extended FORC file and I will look into it.

        Cheers

        Rich

        • Julius De Rojas says:

          Hello Dr. Harrison,

          First, thank you for your efforts, it’s quite a nice package.

          I also seem to not be able to load the “extended range” FORCs produced by the Lakeshore software. Is FORCinel able to handle this format?

          Thanks,

          Julius

          • Richard Harrison says:

            Hi

            I think I fixed this. Have you downloaded the very latest version on the website? It should now have the option to “load extended forcs’ in the FORCinel menu.

            Cheers

            Rich

  25. Axel Forslund says:

    Hello,

    I’m doing FORC measurements with a SQUID and have a few questions about the FORCinel program.

    1. Since the SQUID measurements takes some time, measuring the first Hb values for the last Ha values, that are of no interest for the diagram, seems quite unuseful. Is there any specific reason to why they have to be included in the data? Can I simply make a jump from those Ha values to larger Hb that are shown in the diagram?

    2. When I view the unrotated diagram with FORCinel, I seem to get the data points that I measured. But in the Hu/Hc diagram, there seems to be values for a larger span of Hu and Hc than those given from the definition with Ha and Hb. For example when zooming out slightly in the diagram for bush.txt, there are Hu values as high as 4000 Oe. Where do these points come from?

    Looking forward to hear from you.

    Best regads,
    Axel Forslund

    • Richard Harrison says:

      Hi

      I have not quite understood your question, but it sounds like you want to optimise which points gets measured to save time on the SQUID. I recommend you check out the butterFORC site, which has a labview script to do just this kind of thing. It uses a non-regular FORC acquisition to optimise where the instrument focusses the most time measuring.

      https://sites.google.com/site/butterforc/home

      Cheers

      Rich

  26. Erik Samwel says:

    Hello Dr. Harrison,

    I am trying to make the MicroSense VSM software compatible with the standard set by Princeton so that the data can be imported automatically into your software but I am a bit confused how the values of the script parameters Hb1, Hb2, Hc1, Hc2 and HNCr relate to what data points are actually measured.
    1) How does one determine the start field of the first FORC from the above parameters?
    2) How does one determine the length of the longest FORC curves from those parameters?
    3) What is the meaning of HNCr?

    Once I know the answers to those questions I believe I can modify our software to measure the curves in the same way that the Princeton systems do and the software will be able to export the data in a file compatible with your software.

    Thank you very much in advance.

    Erik

  27. YUE CAO says:

    Hello Dr. Harrison,
    I am from Washington State University. I am using FORCinel to analyze my data collected from Lakeshore PMC 3900. There is one option in PMC system which can allow me to subtract the paramagnetic background. In this case, there will be 4 columns of data in the raw data. First two columns are initial data and, 3rd and 4th are modified data. However, when I load the file to FORCinel, it only read first two columns. Do you have any method to read the 3rd and 4th columns instead of the first two? Thanks very much.

    Yue

    • Richard Harrison says:

      Hi

      Currently it only loads in the first two columns. I could look into this. However, it should be pointed out that performing the paramagnetic correction has no effect whatsoever on the final FORC diagram. The paramagnetic contribution is entirely a reversible contribution to the magnetisation, and completely disappears when you calculate the FORC distribution (a second derivative). Hence, other than for ease of visualisation of the raw FORC curves, there is no need to correct for the paramagnetic contribution before loading and processing the data.

      In fact, if you want to get rid of the reversible contribution and see a clearer representation of the irreversible contribution to the magnetisation, I highly recommend using the ‘Subtract lower branch’ option. This not only lets you see the irreversible contribution more clearly, but gets rid of common processing artefacts (especially when using VARIFORC – also highly recommended).

      See the new FORC processing guide in the download folder for a description of the Subtract Lower Branch option.

      Cheers

      Rich

  28. Ying says:

    Hi Dr. Harrison,

    I am a new user of FORCinel and I am having a little problem when I open FORCinel v2.05.pxp using Igor Pro 6.37. It gives a function compilation error, saying that “name already exists as a fucntion; Error in Image Contrast.ipf:WMCreateImageContrastGraph.” I am wondering what is causing this error and whether there is a quick fix for that.

    Thank you!

    • Richard Harrison says:

      Hi

      Odd, this is a built in function associated with Igor’s image processing routines. I don’t know why it is causing this problem. I think the easiest thing to try is install the latest version (6.38) and see if that solves the issue.

      Let me know if it works.

      Rich

      • Ying says:

        Hi Dr. Harrison,

        Thank you for your help! I tried to open FORCinel v2.05.pxp on another computer and there was no problem at all. Somehow the Igor on my personal laptop (it’s a Macbook) keeps giving me the error, even after I re-installed it and updated it to the latest version. As for now I can just use the other computer to do FORCinel. Hopefully I can figure out what is wrong with the Igor Pro on my laptop soon (I will update you if there is any progress)

        Thank you again for the great package!

      • Ying says:

        Hi Dr. Harrison,

        I think I got the reason. There is a procedure file in the Igor procedure folder on my laptop, in which the name of the function is used. I apologize for the baffling error.

        Thanks for your help!

        • Richard Harrison says:

          Great, glad it is working for you now. Keep an eye out for FORCinel version 3 coming soon(ish).

          Rich

  29. Daniel Hedlund says:

    Hi

    Trying to use FORCinel 2.05 with latest (7.0.0.14 (Build 27280)) gives the following error:
    ambiguous wave point number

    setscale/i x 0,c2,matrix3d
    Error in Procedure:make3d

    • Richard Harrison says:

      Hi

      It is a quick fix and I have an Igor 7 compatible version. I am on holiday at the moment so will post it when it get back.

      Rich

      • Richard Harrison says:

        I have uploaded the new version that will now compile on Igor 7. Note however, that there are still a few issues with running on Igor 7 (mainly related to its new automated multiprocessing). These will all be fixed in the upcoming major release of FORCinel version 3 (expected Dec. 2016). For now I recommend using Igor 6 for FORCinel.

        Rich

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