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Structural and Magnetic Properties of Dilute Spinel Ferrites: Neutron Diffractometry and Magnetometry Investigations |
Journal of Magnetics, Volume 16, Number 2, 30 Jun 2011, Pages 134-139 |
H. Mamiya * (National Institute for Materials Science), N. Terada (National Institute for Materials Science), H. Kitazawa (National Institute for Materials Science), A. Hoshikawa (Ibaraki University), T. Ishigaki (Ibaraki University) |
Abstract |
Magnetic properties of highly zinc-substituted manganese ferrites are discussed on the basis of cation distribution. High throughput neutron powder diffractometry indicates that the prepared samples possess a nearly normal spinel structure, where the substitution of nonmagnetic zinc ions mainly causes the dilution of magnetic ions in the A-sublattice and consequently affects bond-randomness in the B-sublattice. On the other hand, the estimated occupancy of manganese ions in the B site indicates that random anisotropy effects due to local Jahn-Teller distortions gradually weaken with the substitution. Bulk magnetometry indicates that the substitution smears the transition from a paramagnetic phase to a soft-magnetic phase. Furthermore, at lower temperatures, such a soft-magnetic phase is destabilized and a magnetic glassy state appears. These features of the magnetic properties of dilute spinel ferrites are discussed from the viewpoint of the above-mentioned various types of disorders.
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Keywords: oxide spinel; TOF neutron diffraction; diluted ferrimagnet; smeared phase transition; reentrant spin-glass |
DOI: 10.4283/JMAG.2011.16.2.134 |
Full Text: PDF |
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