Magnetic structures at the ferromagnetic NiFe and antiferromagnetic NiMn interface in exchange-biased films: Role of noncollinear magnetism and roughness
Magnetic structures at the ferromagnetic NiFe and antiferromagnetic NiMn interface in exchange-biased films: Role of noncollinear magnetism and roughness
复制标题
交换偏置薄膜中铁磁 NiFe 和反铁磁 NiMn 界面处的磁结构：非共线磁性和粗糙度的作用
DOI：
10.1103/physrevb.65.012402
复制
发表时间：
2001
影响因子：
3.7
通讯作者：
J. Fernandez‐de‐Castro
中科院分区：
文献类型：
--
作者：
K. Nakamura;A. Freeman;Ding;L. Zhong;J. Fernandez‐de‐Castro
用考虑非共线磁性的第一性原理全势线化增广平面波计算方法确定了交换偏置FM NiFe/AFM NiMn薄膜的补偿铁磁/反铁磁(FM/AFM)界面的磁结构.结果表明，FM NiFe层的磁矩与AFM NiMn层的磁矩垂直。界面附近的原子内非共线磁性对稳定垂直耦合起着重要作用，而垂直耦合导致大的双二次交换能(BEE)。BEE足够大，需要在AFMNiMn层中形成磁畴壁(估计厚度为∼370A)，这可能是观察到的大矫直力和交换偏置的原因。我们还讨论了粗略的FM/AFM界面的磁结构--如模型计算中包含线阶跃缺陷所模拟的那样--这可能有助于单向磁各向异性。
The magnetic structures at the compensated ferromagnetic/antiferromagnetic (FM/AFM) interface of exchange bias FM NiFe/AFM NiMn films were determined with first-principles full-potential linearized augmented plane-wave calculations including noncollinear magnetism. The results predict that the magnetic moments of the FM NiFe layer lie perpendicular to those of the AFM NiMn layer. The intra-atomic noncollinear magnetism that arises near the interface is found to play an important role in stabilizing the perpendicular coupling that leads to a large biquadratic exchange energy (BEE). The BEE is large enough to require formation of a magnetic domain wall (with an estimated thickness ∼370 A) in the AFM NiMn layers, which may account for the observed large coercivity and exchange bias. We also discuss magnetic structures at a rough FM/AFM interface-as simulated in model calculations with the inclusion of line step defects-which may contribute to a unidirectional magnetic anisotropy.