We investigate the temperature dependence of the coercive field of a nanogranular co-sputtered Fe/Ag film. The sample is superparamagnetic at room temperature and displays a 3% giant magnetoresistance. As temperature decreases from 40 to 9 K. hysteresis appears in magnetization loops. The coercive field dependence on temperature turns Out to be different from the power law expected for single-domain monodispersed ferromagnetic particle ensembles. The results are analyzed in terms of a model taking into account the effect of magnetic grain size distribution on coercive field. The agreement between experiment and the model is excellent. The possibility to gain information concerning width and symmetry of the particles volume distribution from the study of coercivity's scaling with temperature is discussed.
Coercive field vs temperature in Fe/Ag nanogranular films
BISERO, Diego;ANGELI, Ergisto;SPIZZO, Federico;VAVASSORI, Paolo;RONCONI, Franco
2003
Abstract
We investigate the temperature dependence of the coercive field of a nanogranular co-sputtered Fe/Ag film. The sample is superparamagnetic at room temperature and displays a 3% giant magnetoresistance. As temperature decreases from 40 to 9 K. hysteresis appears in magnetization loops. The coercive field dependence on temperature turns Out to be different from the power law expected for single-domain monodispersed ferromagnetic particle ensembles. The results are analyzed in terms of a model taking into account the effect of magnetic grain size distribution on coercive field. The agreement between experiment and the model is excellent. The possibility to gain information concerning width and symmetry of the particles volume distribution from the study of coercivity's scaling with temperature is discussed.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
