| T O P I C R E V I E W |
| Thanassis |
Posted - 01/23/2018 : 03:53:42 AM
I have been using the HLN equation to fit magnetoconductivity at low temperatures but haven't been able to make a good fit till now. I thought I might take the help on this forum to succeed in it.
Looking forward to your suggestions,
Thanks |
| 3 L A T E S T R E P L I E S (Newest First) |
| Shirley_GZ |
Posted - 02/08/2018 : 04:45:10 AM
Hi Alex,
Origin has a LabTalk function Real_polygamma and an Origin C function real_polygamma which are variants of the digamma function.
https://www.originlab.com/doc/LabTalk/ref/Real-polygamma-func
https://www.originlab.com/doc/OriginC/ref/real_polygamma
With these two functions, you need set k=0, and then use them to define your HLN function. About how to define fitting functions by yourself, please refer to
https://www.originlab.com/index.aspx?go=support/videotutorials&pid=1172
https://www.originlab.com/doc/Tutorials/UserDef-FitFunc
Thanks,
Shirley
Originlab Technical Service Team |
| Alex31 |
Posted - 02/07/2018 : 09:10:52 AM
The Hikami-Larkin-Nagaoka formula is of the form:
Y=a{Ψ(1/2+b/X)-ln(b/X)},
where a,b are fitting parameters and the function Ψ(1/2+b/X) is the digamma function which is defined as the logarithmic first derivative of the gamma function.
Ψ(Χ)=d/dX(lnΓ(Χ))
The problem is that origin does not have the digamma function so that we can use it to built the equation. Is there any way we overcome this problem?
Thank you in advance!
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| Shirley_GZ |
Posted - 01/23/2018 : 04:40:59 AM
Hi,
As I know, Origin doesn't have such built-in equation. So, you defined this fitting function by yourself, right?
Could you send us the FDF file and Origin project file with the fitting results via tech@originlab.com? Also the detailed equation you are following to define the fitting function?
Thanks,
Shirley
Originlab Technical Service Team |
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