An x-ray diffraction and magnetic susceptibility study of

Abstract

Polycrystalline samples of the new semimagnetic semiconductor YbxY2-xO3 (x = 0.06, 0.12, 0.25, 0.39, 1.00, 1.40, 1.80) were obtained by ceramic technology. An x-ray diffraction experiment was performed on all of the samples at room temperature. These data provided the basis for Rietveld refinements. The refinements showed that Yb3+ ions preferentially occupy the 24d position. The lattice constants and the mean cation-anion distances decrease linearly with the Yb3+-ion concentration. The inverse magnetic susceptibilities for all of the samples depend linearly on the temperature for 4 K LT T LT 30 K. In this region only the lowest Kramers doublet is populated, and for that level the effective magnetic quantum number M-1eff. is deduced. The Curie-Weiss paramagnetic temperatures theta(x) obtained from the low-temperature region depend linearly on the concentration x. Over the whole experimental region 4 K LT T LT 250 K, the magnetic susceptibility deviates from the Curie-Weiss law, and its calculation requires inclusion of the first excited Kramers doubler. The effective magnetic quantum number M-2eff and energy gap Delta W of the first excited doublet were deduced.