Influence of the doping on the time-dependent magnetic behaviour of fine particles

Author

Bottoni, Giancarlo ; Candolfo, Donato ; Cecchetti, Antonio

Author_Institution

Dipartimento di Fisica, Ferrara Univ., Italy

Volume

30

Issue

6

fYear

1994

fDate

11/1/1994 12:00:00 AM

Firstpage

4077

Lastpage

4079

Abstract

Time dependent magnetic phenomena are analysed by measuring the changes of magnetization with time in the presence of a constant field on fine particles containing various percentage of dopants. The samples analysed are: iron oxides (Co-doped), CrO₂ (Fe/Sb- and Ir-doped) and Ba ferrite (Co/Ti-doped) particles. The doping causes a large increase of the coefficient S which characterizes the magnetic viscosity, and an increase of the thermal fluctuation field H_f. The “activation volume” V_ac, which is considered as the region of greatest magnetic instability in the particle and the “switching volume” V_c decrease with doping. These effects are principally attributed to the increase of the anisotropy directions distribution inside the particles and to the evolution of the magnetization reversal mode in the modified particles

Keywords

magnetic aftereffect; magnetic anisotropy; magnetic particles; magnetic switching; magnetisation reversal; BaFe₁₂O₁₉:Co,Ti; Co-doped iron oxides; Co/Ti-doped Ba ferrite; CrO₂:Fe,Sb; CrO₂:Ir; Fe/Sb-doped CrO₂; Fe₂O₃:Co; Ir-doped CrO₂; activation volume; anisotropy; doping; fine particles; magnetic instability; magnetic viscosity; magnetization; magnetization reversal; switching volume; thermal fluctuation field; time-dependent magnetic behaviour; Doping; Ferrites; Iron; Magnetic analysis; Magnetic anisotropy; Magnetic field measurement; Magnetization; Particle measurements; Perpendicular magnetic anisotropy; Time measurement;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.333994

Filename

333994