Micromagnetic study of exchange spring media with a rough interface on an example of FePt films

作者：Dymerska Barbara^*; Lee Jehyun; Fidler Josef; Suess Dieter

来源：Journal of Physics D: Applied Physics , 2012, 45(49): 495001.

DOI：10.1088/0022-3727/45/49/495001

In this paper exchange spring media with a rough interface between magnetically hard and soft materials are considered. As an example a nanostructure of FePt L1(0)/A1 films is analysed. The observed features, such as inclusions of L1(0) phase in A1 matrix, were transferred into finite element numerical models. Also, the distribution of the hard phase along the thickness of the medium was analysed. It was found to fit linear, logistic and quadratic functions in the interface region. Micromagnetic simulations show that the position and size of obstacles significantly alter the switching field of the media. Moreover, the minimal switching field of H-sw = 0.9 T was observed for a quadratic L1(0) distribution in an 18 nm thick interface region. The numerical results agree well with an analytical formula of the pinning field of exchange spring media, which is derived for the general case of spatially varying magnetization, anisotropy and exchange constant. It is emphasized that the applicability of the numerical methods described here is not limited to FePt L1(0)/A1 films but could be interesting also for other exchange spring media, such as CoPt L1(0)/A1 or FePt(L1(0))/FeAu(L1(0)).

• 出版日期2012-12-12