We analyze the magnetic properties of mechanically ground nanosized Wi particles dispersed in a SiO(2) matrix. Our magnetic characterization of the as-milled samples show the occurrence of two blocking processes and that of non-monotonic milling time evolutions of the magnetic-order temperature, the high-field magnetization and the saturation Coercivity. The measured coercivities exhibit giant values and a uniaxial-type temperature dependence. Thermal treatment carried out in the as-prepared samples result in a remarkable coercivity reduction and in an increase of the high-field magnetization. We conclude, on the basis of the consideration of a core (pure Wi) and shell (Ni-Si inhomogeneous alloy) particle structure, that the magnetoelastic anisotropy plays the dominant role in determining the magnetic properties of our particles.
Magnetic properties of Ni nanoparticles dispersed in silica prepared by high-energy ball milling
de Julian C;
1998
Abstract
We analyze the magnetic properties of mechanically ground nanosized Wi particles dispersed in a SiO(2) matrix. Our magnetic characterization of the as-milled samples show the occurrence of two blocking processes and that of non-monotonic milling time evolutions of the magnetic-order temperature, the high-field magnetization and the saturation Coercivity. The measured coercivities exhibit giant values and a uniaxial-type temperature dependence. Thermal treatment carried out in the as-prepared samples result in a remarkable coercivity reduction and in an increase of the high-field magnetization. We conclude, on the basis of the consideration of a core (pure Wi) and shell (Ni-Si inhomogeneous alloy) particle structure, that the magnetoelastic anisotropy plays the dominant role in determining the magnetic properties of our particles.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
