Dielectric, magnetic and lattice dynamics properties of Y-type hexaferrite Ba.sub.0.5./sub.Sr.sub.1.5./sub.Zn.sub.2./sub.Fe.sub.12./sub.O.sub.22./sub.. Comparison of ceramics and single crystals

0347513 - FZÚ 2011 RIV US eng J - Journal Article
Kamba, Stanislav - Goian, Veronica - Savinov, Maxim - Buixaderas, Elena - Nuzhnyy, Dmitry - Maryško, Miroslav - Kempa, Martin - Bovtun, Viktor - Hlinka, Jiří - Knížek, Karel - Vaněk, Přemysl - Novák, Pavel - Buršík, Josef - Hiraoka, Y. - Kimura, T. - Kouřil, K. - Štěpánková, H.
Dielectric, magnetic and lattice dynamics properties of Y-type hexaferrite Ba_0.5Sr_1.5Zn₂Fe₁₂O₂₂. Comparison of ceramics and single crystals.
Journal of Applied Physics. Roč. 107, č. 10 (2010), 104109/1-104109/7. ISSN 0021-8979. E-ISSN 1089-7550
R&D Projects: GA MŠMT ME08059; GA AV ČR IAA100100803
Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521; CEZ:AV0Z40320502
Keywords : multiferroics * infrared spectroscopy * phonons * magnon
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 2.064, year: 2010

We prepared multiferroic Y-type hexaferrite Ba0.5Sr1.5Zn2Fe12O22 ceramics and compared their magnetic and dielectric properties with single crystal. Magnetic susceptibility and microwave resonance measurement revealed magnetic phase transition at TC= 312 K, similar as in single crystal. Softening of magnon frequency was observed in the microwave range near TC, but at low temperatures it hardens to THz region on cooling. Ceramics quenched after sintering exhibit several orders of magnitude lower conductivity than the single crystal. Ferroelectric phase can be induced by external magnetic field in all investigated samples and the phase diagram in ceramics qualitatively resembles that of the single crystal. Moreover, we have observed in the single crystal, that the range of magnetic fields, where the ferroelectric phase is induced, broadens after annealing. Number and symmetry of observed infrared and Raman active phonons correspond to paraelectric phase with D3d5 hexagonal structure.
Permanent Link: http://hdl.handle.net/11104/0188279