Limeira V P C, Nagamine L C C M, Geshev J, Cornejo D R, Garanhani F J
Instituto de Física, USP, São Paulo, 05508-090 São Paulo, Brazil.
J Phys Condens Matter. 2019 Jul 3;31(26):265802. doi: 10.1088/1361-648X/ab11ab. Epub 2019 Mar 20.
Magnetization and magnetoresistance properties of Py/Cu/Py/IrMn spin valve (SV) films are studied in the framework of the modified antiferromagnetic domain-wall model applied to a granular multidomain system. In the simulations, a misalignment between the in-plane easy magnetization axes of the Py and IrMn is considered. Magnetization and magnetoresistance data are simulated for a number of field orientations and a fairly good agreement with the experiment is found. The same holds for the respective distributions of the coercive and exchange-bias field values determined from magnetoresistance first-order reversal curves (MR-FORC) obtained for magnetic field parallel to the direction of that applied during the sample deposition. Both experimental and theoretical data of the angular variations of the magnetoresistance at constant fields are successfully used to obtain the misalignment angles. For some samples, mostly those with thinner Py layer coupled to IrMn one, our results indicate that the misalignment is due to interfacial magnetic frustration. Moreover, it is shown that MR-FORC diagrams are useful to extract information about the alignment of the grains along the field-cooling directions in SVs, as well as that these can be used to determine the threshold of the continuity of the pinned magnetic layer.
在应用于颗粒多畴系统的修正反铁磁畴壁模型框架下，研究了Py/Cu/Py/IrMn自旋阀（SV）薄膜的磁化和磁阻特性。在模拟中，考虑了Py和IrMn的面内易磁化轴之间的错位。针对多个场取向模拟了磁化和磁阻数据，并发现与实验结果相当吻合。对于从与样品沉积期间施加的磁场方向平行的磁场获得的磁阻一阶反转曲线（MR-FORC）确定的矫顽场和交换偏置场值的各自分布，情况也是如此。恒定磁场下磁阻角变化的实验和理论数据均成功用于获得错位角。对于一些样品，主要是那些Py层较薄且与IrMn层耦合的样品，我们的结果表明错位是由于界面磁阻挫。此外，结果表明MR-FORC图有助于提取有关SV中晶粒沿场冷方向排列的信息，并且这些图可用于确定钉扎磁层连续性的阈值。
