Mechanism of the exchange-bias field in ferromagnetic and antiferromagnetic bilayers
Mechanism of the exchange-bias field in ferromagnetic and antiferromagnetic bilayers
复制标题
铁磁和反铁磁双层中交换偏置场的机制
DOI：
10.1103/physrevb.68.014437
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发表时间：
2003
影响因子：
3.7
通讯作者：
K. Fukamichi
中科院分区：
文献类型：
--
作者：
C. Mitsumata;A. Sakuma;K. Fukamichi
在经典海森堡模型的框架下，用蒙特卡罗方法研究了铁磁和反铁磁双层中的交换偏置场现象。由磁性和非磁性原子组成的二元合金（如无序γ相反铁磁层）的计算显示出非共线自旋结构。此外，计算的磁化过程由于单向交换偏置场而产生环路偏移。换句话说，由反铁磁层中的几何挫折引起的非共线自旋结构是磁化环位移的原因。另一方面，在有序l10型反铁磁合金中形成的共线自旋结构只导致铁磁层矫顽力的增强。在有序L1 0型反铁磁层中引入多畴后，铁磁层的磁化环位移明显是由磁畴边界处诱导的几何受挫自旋引起的。
Exchange-bias field phenomena in ferromagnetic and antiferromagnetic bilayers have been investigated by means of the Monte Carlo calculations within the framework of the classical Heisenberg model. The calculations for a binary alloy composed of magnetic and nonmagnetic atoms such as a disordered γ-phase antiferromagnetic layer show a noncollinear spin structure. In addition, the calculated magnetization process gives a loop shift due to the unidirectional exchange-bias field. In other words, the noncollinear spin structure caused by the geometric frustrations in the antiferromagnetic layer is responsible for the magnetization loop shift. On the other hand, a collinear spin structure formed in an ordered L 1 0 -type antiferromagnetic alloy results in only the enhancement of coercivity of the ferromagnetic layer. Introducing the multidomains into the ordered L1 0 -type antiferromagnetic layer, however, the magnetization loop shift of the ferromagnetic layer is evidently developed by the geometrically frustrated spins induced at the magnetic domain boundaries.