Tailoring the interfacial exchange coupling of perpendicularly magnetized Co/L10-Mn1.5Ga bilayers
Tailoring the interfacial exchange coupling of perpendicularly magnetized Co/L10-Mn1.5Ga bilayers
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DOI：
10.1088/0022-3727/49/24/245003
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发表时间：
2016-05
期刊：
影响因子：
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通讯作者：
J. Xiao;J. Lu;W. Q. Liu;Y. W. Zhang;Haiquan Wang;L. Zhu;H. Deng;D. Wei;Y. B. Xu;J. Zhao
中科院分区：
文献类型：
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作者：
J. Xiao;J. Lu;W. Q. Liu;Y. W. Zhang;Haiquan Wang;L. Zhu;H. Deng;D. Wei;Y. B. Xu;J. Zhao
利用超导量子干涉仪（SQUID）和X射线磁性圆二色性（XMCD）研究了Co（2-12 MLs）/L_（10）-Mn_（1.5）Ga（15 nm）双层膜在300 °C退火前后的磁性。我们发现，当Co层的厚度小于6个单层时，由于Co层与L10-Mn1.5Ga层之间的耦合，Co层仍能保持垂直磁化，SQUID和XMCD测量都证实了这一点。这种L10-Mn1.5Ga和Co层之间的交换耦合在退火过程之后从铁磁耦合变为反铁磁耦合。此外，通过将L10-Mn1.5Ga表面从富Mn改变为富Ga，磁耦合也可以从铁磁调整为反铁磁。第一性原理计算表明，Mn封端的L10-Mn1.5Ga双层膜的界面耦合类型为铁磁性，而Ga封端的双层膜的界面耦合类型为反铁磁性.根据求和规则计算了Co/L_（10）-Mn_（1.5）Ga双层膜中Co的自旋和轨道磁矩，发现Co的轨道磁矩与自旋磁矩之比并没有像Co/Pd和Co/Pt等垂直磁化的Co基多层膜那样增大.
We have studied the magnetic properties of Co (2–12 MLs)/L10-Mn1.5Ga (15 nm) bilayers without and with annealing at 300 °C by a combination of superconducting quantum interference device (SQUID) magnetometry and x-ray magnetic circular dichroism (XMCD). We find that the Co layer can remain perpendicularly magnetized when its thickness is less than six monolayers due to the coupling between Co and L10-Mn1.5Ga layers, which is doubly confirmed by both SQUID and XMCD measurements. Such an exchange coupling between L10-Mn1.5Ga and Co layers changes from ferromagnetic coupling to antiferromagnetic coupling after the annealing process. Furthermore, the magnetic coupling can also be tailored from ferromagnetic to antiferromagnetic by changing the L10-Mn1.5Ga surface from Mn-rich to Ga-rich. The first-principles calculations show that the interfacial coupling type is ferromagnetic for a Mn-terminated L10-Mn1.5Ga bilayer, while antiferromagnetic for a Ga-terminated bilayer. The spin and orbital moments of Co in the Co/L10-Mn1.5Ga bilayers are calculated according to the sum rules and the ratio of the orbital to spin magnetic moments for Co is not enhanced like other perpendicularly magnetized Co-based multilayers such as Co/Pd and Co/Pt.