title: Structural evolution from Bi4.2K0.8Fe2O9+δ nanobelts to BiFeO3 nanochains in vacuum and their multiferroic properties.
abstract: In this paper, we report the structural evolution of Bi(4.2)K(0.8)Fe(2)O(9+δ) nanobelts to BiFeO3 nanochains and the related variations in multiferroic properties. By using in situ transmission electron microscopy with comprehensive characterization, it was found that the layered perovskite multiferroic Bi(4.2)K(0.8)Fe(2)O(9+δ) nanobelts were very unstable in a vacuum environment, with Bi being easily removed. Based on this finding, a simple vacuum annealing method was designed which successfully transformed the Bi(4.2)K(0.8)Fe(2)O(9+δ) nanobelts into one-dimensional BiFeO(3) nanochains. Both the Bi(4.2)K(0.8)Fe(2)O(9+δ) nanobelts and the BiFeO3 nanochains showed multiferroic behavior, with their ferroelectric and ferromagnetic properties clearly established by piezoresponse and magnetic measurements, respectively. Interestingly, the BiFeO(3) nanochains had a larger magnetization than the Bi(4.2)K(0.8)Fe(2)O(9+δ) nanobelts. Moreover, the BiFeO(3) nanochains exhibited a surprisingly large exchange bias with small training effects. This one-dimensional BiFeO(3) multiferroic nanostructure characterized by a relatively stable exchange bias offers important functionalities that may be attractive for device applications.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei 230026, P. R. China. lixg@ustc.edu.cn.
authors.forename: Sining
authors.initials: S
authors.lastname: Dong
authors.forename: Dalong
authors.initials: D
authors.lastname: Zhang
authors.forename: Yukuai
authors.initials: Y
authors.lastname: Liu
authors.forename: Shengwei
authors.initials: S
authors.lastname: Yang
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.forename: Yuewei
authors.initials: Y
authors.lastname: Yin
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Li