Micromagnetic Studies on Tunneling Magnetoresistive Spin Valves
Micromagnetic Studies on Tunneling Magnetoresistive Spin Valves
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DOI：
10.1109/tmag.2011.2148169
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发表时间：
2011-09
影响因子：
2.1
通讯作者：
Yi Wang;D. Wei;K. Gao
中科院分区：
文献类型：
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作者：
Yi Wang;D. Wei;K. Gao
建立了一个微磁模型来模拟多晶TMR自旋阀的磁阻(R-H)环，其中钉扎层(PL)交换偏置到反铁磁(AFM)层。在铁磁自由层和光致发光中引入了两个相：晶内的体心立方晶相和晶界的非晶相，这两个相在自由层和光致发光中具有不同的磁参数。各向异性的立方易晶轴对于颗粒内的所有微磁性晶胞都是均匀的，但在晶界上是随机取向的。假设只在部分晶体中，从AFM层到光致发光的钉扎场Hpin不为零，并且Hpin在晶体中具有广泛的分布。本文计算了光致发光中具有50%和25%偏置颗粒的R-H回线，与实验结果相一致。此外，光致发光中Hpin的宽幅分布和弱的晶间交换是模拟光致发光倾斜的R-H环的基本因素。
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.