Synthesis of single-crystalline BiFeO₃ nanoparticles and their magnetic properties

ABSTRACT

Single-crystalline multiferroic BiFeO₃ (BFO) nanoparticles with R3c space group have been synthesized via sol-gel process. The BFO nanoparticles exhibit weak ferromagnetism at low temperatures and antiferromagnetic behavior at room temperature. An unexpected abrupt increase of the magnetization at ∼ 10 K was found in the ZFC curve, which could be ascribed to a competition between the ferromagnetization (particle sizes below 62 nm) and anti-ferromagnetization (particle sizes over 62 nm). In addition, M-H loops reveal an exchange bias effect in the BFO nanoparticles, which reaches a maximum at 10 K.

KEYWORDS:

• BiFeO₃ nanoparticles
• sol-gel processing
• magnetic properties

Funding

This work is partially supported by the National Natural Science Foundation of China (grant nos. 11674161, 11174122 and 11134004); National Basic Research Program of China (grant no. 2015CB654900); open projects from State Key Laboratory of Materials-Oriented Chemical Engineering (MCE), Nanjing University of Technology (grant no. KL14–10); six big talent peak project from Jiangsu Province (grant no. XCL-004) and National Laboratory of Solid State Microstructures, Nanjing University.