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. T he X-ray powder diffraction data were collected and the crystal struct ures 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 su perexchange interaction were determined. Magnetic susceptibility measu rements were done by the Faraday method in the temperature range 290 t o 620 K and a behaviour in accordance with the Curie-Weiss law was obt ained. The molar Curie's constants linearly depend on concentration. T he effective magnetic moments of Ho3+ ions were smaller than the free ion value. The Curie-Weiss paramagnetic temperatures indicated antifer romagnetic interaction. The gram ion susceptibilities confirmed the ra ndom 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 s ample with x = 0.10. The nonlinearity of Curie-Weiss paramagnetic temp eratures 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.