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Optical and magneto-optical studies of a multiferroic GaFeO3 with a high Curie temperature

2005; Pleiades Publishing; Volume: 81; Issue: 9 Linguagem: Inglês

10.1134/1.1984028

1090-6487

A. M. Kalashnikova, R. V. Pisarev, Л. Н. Безматерных, V. L. Temerov, A. Kirilyuk, Th. Rasing,

Ferroelectric and Piezoelectric Materials

Single crystals of a noncentrosymmetric orthorhombic pyroelectric ferrimagnet Ga2−x FexO3 with a Curie temperature within 260–345 K have been grown by the flux method. It has been found that the electrical properties of the single crystals varied over a broad range from 105 to 1013 Ω cm depending on the presence of transitionmetal oxide impurities. The dispersion relations for all three principal dielectric functions of orthorhombic GaFeO3 have been determined in the range 0.7–5.4 eV by spectroscopic ellipsometry. The spectra of the dielectric functions of the orthorhombic Ga2−x FexO3 crystals are compared with the spectra of the trigonal crystals. The Faraday effect and second-harmonic generation are studied, and the law of the transition to the paramagnetic state has been determined. The crystallographic and magnetic contributions to the second-harmonic generation are analyzed.