Actually I am working on a ferrite material. And I want to study the spin wave excitation in the material. Since the uniform FMR mode is considered as the lowest energy magnon, how I can analyse an FMR spectrum? What are the possible parameters that can be studied by FMR spectrum of my sample?
1.Если образец является кубическим монокристаллом, то из спектра однородного ФМР для разной ориентации образца в магнитном поле можно определить константы анизотропии, параметр затухания и гиромагнитное отношение. Если взять образец в виде сферы, цилиндра или пленки, то можно определить намагниченность насыщения образца.
2.Спин-волновой резонанс можно возбудить в образце с малым затуханием (узкой линией однородного ФМР).
There are two basic properties that you can learn from the FMR: (i) magnetic anisotropy and (ii) magnetic damping. However, to extract useful parameters that you can compare with values determined by other experimental approaches you have to take into account the geometry of your particular Experiment. Moreover, you have to know the magnetization of your sample from an Independent measurement such as VSM or SQUID magnetometry. I guess that you are working with thin films. In this case: For your analysis I suggest the paper from M. Farle providing a comprehensive introduction to FMR ( REPORTS ON PROGRESS IN PHYSICS Volume: 61 Issue: 7 Pages: 755-826 Published: JUL 1998 ).
If your samples are bulk samples the analysis will significantly depend on the shape of your samples.
To add some comments on what H. J. Elmers has been mentioned above:
FMR is an informative tools that can be used to get from the resonance curve:
(1) position of the resonance field (Hr)
(2) resonance width (dH)
(3) the resonance intensity (I)
(4) the shape of the resonance curve
(5) the number of resonances
the resonance frequency depends on the effective field which is a contribution sum of many resources which include
(a) the external magnetic field
(b) the magnetocrystalline anisotropy field
(c) shape anisotropy field
(d) surface anisotropy
(e) defects and stress anisotropies
(f) magnetostatic (dipole - dipole) field
at first the most important thing to look at the sample shape to avoid the effects of some field sources and study the other effects
the sample shape should be of thin films or spherical bulk
second we have to look at the field direction
and then you have to fit the resonance curve to a Lorentzian, Gaussian or any other function to extract the last parameters and see how curves are deviated from the Lorentzian and so on
you can see some relevant articles
https://www.researchgate.net/publication/324223352_FMR_Studies_on_Nanocrystalline_Zinc_Ferrite_Thin_Films
Thank you very much @Shkar, @Elmers, @Sultan. I will go through the articles, all of you suggested.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Waves