Open AccessExchange bias effect in single crystalline phase MnO nanoparticles
Author(s) -
Ying Luo,
Guoping Zhao,
HT Yang,
NN Song,
Xiang Ren,
HF Ding,
Zhen Cheng
Publication year - 2013
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.62.176102
Subject(s) - materials science , nanoparticle , superparamagnetism , antiferromagnetism , phase (matter) , high resolution transmission electron microscopy , exchange bias , chemical engineering , inert , inert gas , magnetization , nanotechnology , condensed matter physics , transmission electron microscopy , magnetic field , composite material , chemistry , physics , magnetic anisotropy , organic chemistry , quantum mechanics , engineering
The MnO nanoparticles with uniform size (15 nm) and shape have been synthesized in an inert atmosphers by high-temperature oil phase method. XRD patterns and HRTEM reveals that the as-synthesized MnO nanoparticles are of pure crystalline phase. TEM image shows that the MnO nanoparticles are in spherical shape with a narrow size distribution. Both oil phase and the nanoparticles protected with inert gas in the synthesis process can avoid the oxidization of Mn2+. The obvious exchange bias effect can be observed from the M-H loop of MnO nanoparticles under zero field cooling (ZFC) and FC measurements. Furthermore, the temperature-dependent AC susceptibility of the MnO nanoparticles reveals that the exchange bias effect originates from the antiferromagnetic MnO core and the spin-glass surface, rather than the superparamagnetic phase.