DocumentCode :
1332360
Title :
Micromagnetic Studies on Tunneling Magnetoresistive Spin Valves
Author :
Yi Wang ; Dan Wei ; Kai-Zhong Gao
Author_Institution :
Dept. of Mater. Sci. & Eng., Tsinghua Univ., Beijing, China
Volume :
47
Issue :
10
fYear :
2011
Firstpage :
2720
Lastpage :
2723
Abstract :
A micromagnetic model is set up to simulate the magnetoresistive (R-H) loops of a polycrystalline TMR spin valve, in which the pinned layer (PL) is exchange biased to an antiferromagnetic (AFM) layer. In the ferromagnetic free layer (FL) and PL, two phases are introduced: the BCC crystal phase in the grain and the amorphous phase at the grain boundary, which have different magnetic parameters in FL and PL. The cubic easy crystal axes of the anisotropy are uniform for all micromagnetic cells inside a grain, but it is randomly oriented at the grain boundary. It is assumed that, only in part of the grains, the pinning field Hpin from the AFM layer to the PL is not zero; furthermore, Hpin has a wide distribution among crystal grains. In this paper, the R-H loops with 50% and 25% of biased grains in the PL are calculated, and they are consistent with experiments. Moreover, the wide magnitude distribution of Hpin and the weak inter-grain exchange in the PL are the essential factors in our model to simulate the inclined R-H loop of PL.
Keywords :
amorphous state; antiferromagnetism; exchange interactions (electron); ferromagnetism; grain boundaries; magnetic anisotropy; magnetic hysteresis; magnetic multilayers; micromagnetics; spin valves; tunnelling magnetoresistance; BCC crystal phase; amorphous phase; antiferromagnetic layer; crystal grains; exchange bias; ferromagnetic free layer; grain boundary; intergrain exchange; magnetoresistive loops; micromagnetic model; pinned layer; polycrystalline TMR spin valve; tunneling magnetoresistive spin valves; Amorphous magnetic materials; Crystals; Magnetic multilayers; Magnetic separation; Magnetic tunneling; Micromagnetics; Tunneling magnetoresistance; Exchange bias; hysteresis loop; micromagnetic; spin valve;
fLanguage :
English
Journal_Title :
Magnetics, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9464
Type :
jour
DOI :
10.1109/TMAG.2011.2148169
Filename :
6028210
Link To Document :
بازگشت