Structual and Magnetic Properties of MFe2O4 (M=Ni, Mg) Nano Hollow Spheres
Structual and Magnetic Properties of MFe2O4 (M=Ni, Mg) Nano Hollow Spheres
Kensuke Konishi(Ehime University); Taiga Sakurai(Ehime University); Yutaro Nagano(Ehime University); Naoto Manabe(Ehime University); Yugo Morimoto(Ehime University)
63권 3호, 672~675쪽
초록
Sub-micrometer-sized hollow spheres assembled from MFe2O4 (M= Ni, Mg) nanoparticles havebeen prepared by using the template method with a wet chemical process. A superparamagnetictypeblocking process is observed in the zero-field-cooled (ZFC) and the field-cooled (FC) magnetizationsand magnentic susceptibilities. Furthermore, a spin-glass-like behavior due to surfacespin freezing is found in Ni-ferrite nanoparticles. The surface spin freezing temperatures Tf arequite a bit lower than the blocking temperature, and the magnetic field dependence is differentbetween the nanoparticles and the fabricated hollow spheres. The spin-glass nature of the Ni-ferritenanoparticle is demonstrated by the magnetice field dependence of Tf following the well knownAlmeida-Thouless (AT) line. In contrast, the Tf(H) of the hollow Ni-ferrite sphere hints at failureof the Gabay-Toulouse theory as well as the AT theory.
Abstract
Sub-micrometer-sized hollow spheres assembled from MFe2O4 (M= Ni, Mg) nanoparticles havebeen prepared by using the template method with a wet chemical process. A superparamagnetictypeblocking process is observed in the zero-field-cooled (ZFC) and the field-cooled (FC) magnetizationsand magnentic susceptibilities. Furthermore, a spin-glass-like behavior due to surfacespin freezing is found in Ni-ferrite nanoparticles. The surface spin freezing temperatures Tf arequite a bit lower than the blocking temperature, and the magnetic field dependence is differentbetween the nanoparticles and the fabricated hollow spheres. The spin-glass nature of the Ni-ferritenanoparticle is demonstrated by the magnetice field dependence of Tf following the well knownAlmeida-Thouless (AT) line. In contrast, the Tf(H) of the hollow Ni-ferrite sphere hints at failureof the Gabay-Toulouse theory as well as the AT theory.
- 발행기관:
- 한국물리학회
- 분류:
- 물리학