Magnetic Study of M-type Doped Barium Ferrite Nanocrystalline Powders

Abstract

We have studied the static magnetic properties of three different M-type doped barium ferrite compounds prepared by the glass crystallization method. The zero-field-cooled (ZFC) and field-cooled (FC) processes have been recorded at low field and they all show the typical features of a small particle system. The ZFC curves display a broad peak at a temperature T M, which depends on the distribution of particle volumes in the sample. Isothermal magnetization curves M(H) at several temperatures and saturation magnetization M s as a function of temperature have been measured for the Co-Ti sample (BaFe 10.4Co 0.8Ti 0.8O 19). The dependence on temperature of the macroscopic magnetic parameters has been analyzed. The distribution of blocking temperatures is studied from the derivative of the remanent-to-saturation magnetization ratio with respect to temperature and it is fitted to a lognormal distribution, leading to a mean blocking temperature 〈T B〉=(81±40) K. The distribution of volumes of the magnetic unit is also obtained from this fitting. The dependence on temperature of the coercive field follows a T k-law below 35 K. The value of the k exponent is discussed within the scope of two models: (i) the aligned case (k=0.5) and (ii) the random case (k=0.77).

Department(s)

Chemistry

International Standard Serial Number (ISSN)

0021-8979

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1993 American Institute of Physics (AIP), All rights reserved.

Publication Date

01 Jan 1993

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