Premium
Study on new magnetization property and its micro‐mechanism that occurred in anti‐ferromagnetic NiO nanoflowers with nearly uniform size
Author(s) -
Xia Lei,
Li Wanyu,
Wang ChunXiao,
Zhang Yan,
Jiang JianZhong,
Zhang ShuLin
Publication year - 2014
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4547
Subject(s) - raman spectroscopy , magnetization , curie temperature , condensed matter physics , ferromagnetism , magnon , magnetism , spins , non blocking i/o , superparamagnetism , chemistry , magnetic refrigeration , materials science , magnetic field , physics , optics , biochemistry , quantum mechanics , catalysis
Temperature‐dependent magnetization and magnon Raman spectra were measured for anti‐ferromagnetic NiO‐nanoflowers. The results show several new magnetic behaviors, including the appearance of a ferromagnetic phase, a reduced Néel temperature ( T N ) and a reduced Curie temperature ( T C ). The temperature dependencies of the double magnon (2 M) Raman wavenumber and intensity are similar to those of magnetization. A magnetic granules model (MGM) consisted of a crystalline core enclosed by a shell is proposed. The model suggests that the large quantity of spins induced by specific surface effect in the shell plays a key role in nano‐magnetism. Based on the MGM, the micro‐mechanism of the observed new magnetic behavior is understood by the magnon Raman spectra. The MGM is based on the general features of magnetic nano‐particles, and thus it should be generally applicable to common magnetic nano‐particles. Copyright © 2014 John Wiley & Sons, Ltd.