| MMM : mmm intermag 2022 | |||||
| 작성자 | 김** | 작성일 | 2022-05-04 | 조회수 | 140 |
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Oral Presentation Donghyeon Lee Stoner-Wohlfarth Model with Standard Deviation of Magnetic Easy Axis
A granular magnetic film is a well-known material system for achieving ultra-high density recording media. This material system consists of small grains on the scale of a few nanometers, typically separated by boundaries a few nanometers thick. FePt-C is the most popular material in the hard disk drive industry. FePt can be deposited as an L10 structure on MgO (100). [1] C is placed on the MgO layer with surrounding L10 structured FePt grains. [2] As such, nano-size separation of a magnetic material having excellent thermal stability can be achieved in a thin film. The grain size of the film varies from 7 nm to 20 nm. The Stoner-Wohlfarth model (SW model) is known to be a suitable model for explaining the relationship between the magnetic field and the magnetization direction of a single particle. FePt grains with an L10 structure have a very high magnetic anisotropy constant, which enables high thermal stability and single particle magnetization behavior. Though the grains should have magnetic single domains due to the small size less than 15 nm, the angular dependence of the switching field does not match the existing SW model for a single particle. In this presentation, we propose the Stoner-Wohlfarth model with standard deviation of the magnetic easy axis to understand the magnetization switching behavior of the FePt-C granular film. In our model, we can quantify the degree of deviation of the magnetic easy axis in the FePt-C granular film.
[1] Wanjiao Zhu et al, J. Phys.: Condens. Matter, 25, 396001 (2013)
[2] H. Pandey et al., IEEE Trans. Magn., 52, 3200108 (2016)
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