Exchange bias on polycrystalline BiFeO₃/Co₂Fe(Al_0.5Si_0.5) heterostructures

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• 作者：Shi-Zhe Wu ; Yong Wu ; Shao-Qian Yin ; Xiao-Guang Xu ; Jun Miao ; Yong Jiang
• 关键词：Exchange bias ; BiFeO3 ; Polycrystalline ; Domain walls
• 刊名：Rare Metals
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：36
• 期：1
• 页码：32-36
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Metallic Materials; Nanotechnology; Ceramics, Glass, Composites, Natural Materials; Surfaces and Interfaces, Thin Films; Inorganic Chemistry; Physical Chemistry;
• 出版者：Nonferrous Metals Society of China
• ISSN：1867-7185
• 卷排序：36

文摘

Polycrystalline antiferromagnetic BiFeO₃ (BFO) thin films were grown on Si/SiO₂/Ti/Pt (111) substrates by pulsed laser deposition and then ferromagnetic films Co₂Fe(Al_0.5Si_0.5) (CFAS) by magnetron sputtering. After fabrication, the films were vacuum-annealed under a 0.1-T magnetic field at different temperatures from 150 to 500 °C. The exchange bias field can be tuned by the annealing temperature for the heterostructures, and the electric domain size can be controlled by the crystal grain size. A large exchange bias of about 5 × 10−3 T is observed in one of the samples. It can be speculated that the crystal grain sizes are the key element in determining the exchange bias and coercivity of the films annealed at the temperature of higher than Neel temperature (T_N) of BFO. Furthermore, it is possible to extend spin theories from single-crystal BFO system to polycrystalline BFO system.