Single-Crystal BiFeO3 Nanoplates with Robust Antiferromagnetism

Xin Yang; RongGuang Zeng; ZhaoHui Ren; YanFei Wu; Xing Chen; Ming Li; JiaLu Chen; RuoYu Zhao; DiKui Zhou; ZhiMin Liao; He Tian; YunHao Lu; Xiang Li; JiXue Li; GaoRong Han

doi:10.1021/acsami.7b17449

Single-Crystal BiFeO₃ Nanoplates with Robust Antiferromagnetism

ACS Appl Mater Interfaces. 2018 Feb 14;10(6):5785-5792. doi: 10.1021/acsami.7b17449. Epub 2018 Feb 5.

Authors

Xin Yang^{1

2}, RongGuang Zeng³, ZhaoHui Ren¹, YanFei Wu⁴, Xing Chen⁵, Ming Li¹, JiaLu Chen¹, RuoYu Zhao¹, DiKui Zhou¹, ZhiMin Liao⁶, He Tian⁵, YunHao Lu¹, Xiang Li¹, JiXue Li⁵, GaoRong Han¹

Affiliations

¹ State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Application, Zhejiang University , Hangzhou 310027, China.
² Key Laboratory of Advanced Technique & Preparation for Renewable Energy Materials, Ministry of Education, Yunnan Normal University , Kunming 650500, China.
³ Science and Technology on Surface Physics and Chemistry Laboratory , P.O. Box 718-35, Mianyang 621907, China.
⁴ Institute for Quantum Science and Engineering and Department of Physics, South University of Science and Technology of China , Shenzhen 518055, China.
⁵ Center of Electron Microscope, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China.
⁶ State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University , Beijing 100871, China.

PMID: 29368504
DOI: 10.1021/acsami.7b17449

Abstract

Freestanding and single-crystal BiFeO₃ (BFO) nanoplates have been successfully synthesized by a fluoride ion-assisted hydrothermal method, and the thickness of the nanoplates can be effectively tailored from 80 to 380 nm by the concentration of fluoride ions. It is revealed that BFO nanoplates grew via an oriented attachment of layer by layer, giving rise to the formation of the inner interface within the nanoplates. In particular, antiferromagnetic (AFM) phase-transition temperature (Néel temperature, T_N) of the BFO nanoplates is significantly enhanced from typical 370 to ∼512 °C, whereas the Curie temperature (T_C) of the BFO nanoplates is determined to be ∼830 °C, in good agreement with a bulk value. The combination of scanning transmission electron microscopy, electron energy loss spectroscopy, and the first-principle calculations reveals that the interfacial tensile strain remarkably improves the stability of AFM ordering, accounting for the significant enhancement in T_N of BFO plates. Correspondingly, the tensile strain induced the polarization and oxygen octahedral tilting has been observed near the interface. The findings presented here suggest that single-crystal BFO nanoplate is an ideal system for exploring an intrinsic magnetoelectric property, where a tensile strain can be a very promising approach to tailor AFM ordering and polarization rotation for an enhanced coupling effect.

Keywords: BiFeO3 nanoplates; antiferromagnetism; fluoride ion-assisted hydrothermal method; interfacial tensile strain.