Nayak Sagarika, Das Sudhansu Sekhar, Singh Braj Bhusan, Charlton Timothy R, Kinane Christy J, Bedanta Subhankar
Laboratory for Nanomagnetism and Magnetic Materials (LNMM), School of Physical Sciences, National Institute of Science Education and Research (NISER), HBNI P.O. Bhimpur Padanpur, Via-Jatni 752050 India
Oak Ridge National Laboratory 1 Bethel Valley Rd Oak Ridge TN 37830 USA.
RSC Adv. 2020 Sep 15;10(56):34266-34275. doi: 10.1039/d0ra05429a. eCollection 2020 Sep 10.
We present a comprehensive study on the magnetization reversal in the Fe/NiFe bilayer system by alternating the order of the magnetic layers. All the samples show growth-induced uniaxial magnetic anisotropy due to the oblique angle deposition technique. Strong interfacial exchange coupling between the Fe and NiFe layers leads to single-phase hysteresis loops in the bilayer system. The strength of coupling being dependent on the interface changes upon alternating the order of magnetic layers. The magnetic parameters such as coercivity , and anisotropy field become almost doubled when a NiFe layer is grown over the Fe layers. This enhancement in the magnetic parameters is primarily dependent on the increase of the thickness and magnetic moment of the Fe-NiFe interfacial layer as revealed from the polarized neutron reflectivity (PNR) data of the bilayer samples. The difference in the thickness and magnetization of the Fe-NiFe interfacial layer indicates the modification of the microstructure by alternating the order of the magnetic layers of the bilayers. The interfacial magnetic moment increased by almost 18% when the NiFe layer was grown over the Fe layer. In spite of the different values of anisotropy fields and modified interfacial exchange coupling, the Gilbert damping constant values of the ferromagnetic bilayers remain similar to the single NiFe layer.
我们通过改变磁性层的顺序，对Fe/NiFe双层系统中的磁化反转进行了全面研究。由于倾斜角沉积技术，所有样品都表现出生长诱导的单轴磁各向异性。Fe层和NiFe层之间强烈的界面交换耦合导致双层系统中出现单相磁滞回线。耦合强度取决于界面，在改变磁性层顺序时会发生变化。当NiFe层生长在Fe层之上时，矫顽力等磁性参数以及各向异性场几乎翻倍。如双层样品的极化中子反射率（PNR）数据所示，磁性参数的这种增强主要取决于Fe-NiFe界面层厚度和磁矩的增加。Fe-NiFe界面层厚度和磁化强度的差异表明，通过改变双层磁性层的顺序可以改变微观结构。当NiFe层生长在Fe层之上时，界面磁矩增加了近18%。尽管各向异性场的值不同且界面交换耦合有所改变，但铁磁双层的吉尔伯特阻尼常数与单个NiFe层的值相似。
