Magnetization and ferromagnetic resonance (FMR) experiments have been performed on 3 nm NiO noninteracting nanoparticles. The results indicate that the high temperature behavior is determined by the noncompensated moments of particle core, whose blocking is centered at T[approximate]60 K [field dependent maximum of the zero-field-cooled (ZFC) magnetization]. On the other hand, the low temperature behavior is determined by surface cluster spins whose thermal fluctuations freeze in a cluster-glass-like state at T[approximate]15 K (weakly field dependent maximum of ZFC magnetization), giving the major contribution to the effective anisotropy, as shown by the rapid increase of coercivity, remanent magnetization, and confirmed by the temperature dependence of signal intensity, resonant field, and linewidth of FMR spectra.
Surface anisotropy effects in NiO nanoparticles
Fiorani D
2005
Abstract
Magnetization and ferromagnetic resonance (FMR) experiments have been performed on 3 nm NiO noninteracting nanoparticles. The results indicate that the high temperature behavior is determined by the noncompensated moments of particle core, whose blocking is centered at T[approximate]60 K [field dependent maximum of the zero-field-cooled (ZFC) magnetization]. On the other hand, the low temperature behavior is determined by surface cluster spins whose thermal fluctuations freeze in a cluster-glass-like state at T[approximate]15 K (weakly field dependent maximum of ZFC magnetization), giving the major contribution to the effective anisotropy, as shown by the rapid increase of coercivity, remanent magnetization, and confirmed by the temperature dependence of signal intensity, resonant field, and linewidth of FMR spectra.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
