Krichevtsov Boris, Korovin Alexander, Fedorov Vladimir, Suturin Sergey, Levin Aleksandr A, Telegin Andrey, Balashova Elena, Sokolov Nikolai
Ioffe Institute, Politechnicheskaya 26, 194021 St. Petersburg, Russia.
Laboratory of Renewable Energy Sources, Alferov University, Khlopin St. 8/3, 194021 St. Petersburg, Russia.
Nanomaterials (Basel). 2024 Nov 23;14(23):1883. doi: 10.3390/nano14231883.
Thin (~50 nm thick) BaM hexaferrite (BaFeO) films were grown on (1-102) and (0001) cut α-AlO (sapphire) substrates via laser molecular beam epitaxy using a one- or two-stage growth protocol. The advantages of a two-stage protocol are shown. The surface morphology, structural and magnetic properties of films were studied using atomic force microscopy, reflected high-energy electron diffraction, three-dimensional X-ray diffraction reciprocal space mapping, powder X-ray diffraction, magneto-optical, and magnetometric methods. Annealed BaFeO/AlO (1-102) structures consist of close-packed islands epitaxially bonded to the substrate. The hexagonal crystallographic axis and the easy axis (EA) of the magnetization of the films are deflected from the normal to the film by an angle of ~60°. The films exhibit magnetic hysteresis loops for both in-plane and out-of-plane magnetic fields. The shape of () and () hysteresis loops strongly depends on the azimuth of the , confirming the tilted orientation of the EA. The () magnetization curves are caused by the reversible rotation of magnetization and irreversible magnetization jumps associated with the appearance and motion of domain walls. In the absence of a magnetic field, the magnetization is oriented at an angle close to .
通过激光分子束外延技术，采用单阶段或两阶段生长方案，在（1-102）和（0001）切割的α-Al₂O₃（蓝宝石）衬底上生长了厚度约为50纳米的钡铁氧体（BaFe₁₂O₁₉）薄膜。展示了两阶段方案的优势。使用原子力显微镜、反射高能电子衍射、三维X射线衍射倒易空间映射、粉末X射线衍射、磁光和磁力测量方法研究了薄膜的表面形貌、结构和磁性。退火后的BaFe₁₂O₁₉/Al₂O₃（1-102）结构由外延键合到衬底上的密堆积岛组成。薄膜的六方晶轴和易磁化轴（EA）与薄膜法线偏离约60°角。薄膜在面内和面外磁场下均表现出磁滞回线。（）和（）磁滞回线的形状强烈依赖于磁场的方位角，证实了易磁化轴的倾斜取向。（）磁化曲线是由与畴壁的出现和运动相关的磁化可逆旋转和不可逆磁化跳跃引起的。在没有磁场的情况下，磁化方向与接近。
