STRUCTURE PROPERTIES AND MAGNETIC-SUSCEPTIBILITY OF DILUTED MAGNETIC SEMICONDUCTOR Y2-XHOXO3

The polycrystalline samples of Y2-xHoxO3 (0.10 less than or equal to x less than or equal to 1.80) were synthesized by ceramic technology. The X-ray powder diffraction data were collected and the crystal structures were refined by the Rietveld method for the samples Y2-xHoxO3 (x = 0.00, 0.20, 0.40, 1.20, 1.80, 2.00). Holmium ions Ho3+ were randomly distributed over two cationic sites 8b and 24d in the space group Ia3 in all refined structures. Cation-anion-cation bonds important for superexchange interaction were determined. Magnetic susceptibility measurements were done by the Faraday method in the temperature range 290 to 620 K and a behaviour in accordance with the Curie-Weiss law was obtained. The molar Curie's constants linearly depend on concentration. The effective magnetic moments of Ho3+ ions were smaller than the free ion value. The Curie-Weiss paramagnetic temperatures indicated antiferromagnetic interaction. The gram ion susceptibilities confirmed the random distribution of Ho3+ ions over two crystallographic sites in the concentration range 0.20 less than or equal to x less than or equal to 2.00 and pointed to the random distribution of magnetic ions in the sample with x = 0.10. The nonlinearity of Curie-Weiss paramagnetic temperatures versus concentration occurred in the low concentration region (x less than or equal to 0.40), indicating tendency of magnetic ions to form small clusters around cationic sites.