Exchange bias on polycrystalline BiFeO3/CO2Fe（Al0.5Si0.5）heterostructures

• Published in: 稀有金属：英文版 Vol. 36; no. 1; pp. 32 - 36
• Main Author: Shi-Zhe Wu Yong Wu Shao-Qian Yin Xiao-Guang Xu Jun Miao Yong Jiang
• Format: Journal Article
• Language: English
• Published: 2017
• Subjects: bias; BiFe03; Exchange; Polycrystalline;Domain; walls
• ISSN: 1001-0521; 1867-7185

Polycrystalline antiferromagnetic BiFeO3 （BFO）thin films were grown on Si/SiO2/Ti/Pt （111） substrates bypulsed laser deposition and then ferromagnetic filmsCO2Fe（Al0.5Si0.5） （CFAS） by magnetron sputtering. Afterfabrication, the films were vacuum-annealed under a 0.1-Tmagnetic field at different temperatures from 150 to 500 ℃.The exchange bias field can be tuned by the annealing tem-perature for the heterostructures, and the electric domain sizecan be controlled by the crystal grain size. A large exchangebias of about 5 × 10^3 T is observed in one of the samples. Itcan be speculated that the crystal grain sizes are the key ele-ment in determining the exchange bias and coercivity of thefilms annealed at the temperature of higher than Neel tem-perature （TN） of BFO. Furthermore, it is possible to extendspin theories from single-crystal BFO system to polycrys-talline BFO system.