Magnetic reversal processes and critical thickness in FePt/α-Fe/FePt trilayers

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:323

Article

Guo, N. L.¹  Zhao, G. P.^1,2,3  Zhang, H. W.²  Zhou, X. L.¹  Deng, Y.¹ 

[1] Sichuan Normal Univ, Coll Phys & Elect Engn, Chengdu 610068, Peoples R China

[2] Univ Elect Sci & Technol China, State Key Lab Elect Thin Films & Integrated Devic, Chengdu 610054, Peoples R China

[3] Chinese Acad Sci, Inst Phys, Beijing 100190, Peoples R China

关键词: Nucleation field;    Hysteresis loop;    Critical thickness;   

DOI  :  10.1016/j.jmmm.2011.06.050

来源: Elsevier

【 摘 要 】

Magnetic reversal processes of a FePt/alpha-Fe/FePt trilayer system with in-plane easy axes have been investigated within a micromagnetic approach. It is found that the magnetic reversal process consists of three steps: nucleation of a prototype of domain wall in the soft phase, the evolution as well as the motion of the domain wall from the soft to the hard phase and finally, the magnetic reversal of the hard phase. For small soft layer thickness L(s), the three steps are reduced to one single step, where the magnetizations in the two phases reverses simultaneously and the hysteresis loops are square with nucleation as the coercivity mechanism. As L(s) increases, both nucleation and pinning fields decrease. In the meantime, the single-step reversal expands to a standard three-step one and the coercivity mechanism changes from nucleation to pinning. The critical thickness where the coercivity mechanism alters, could be derived analytically, which is found to be inversely proportional to the square root of the crystalline anisotropy of the hard phase. Such a scaling law might provide an easy way to test the present theory. Further increase of L(s) leads to the change of the coercivity mechanism from pinning to nucleation. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

Free