New scheelite-type Cd1−3x⌷xGd2x(MoO4)1−3x(WO4)3x ceramics – their structure, thermal and magnetic properties

Abstract

Polycrystalline samples of scheelite-type Cd1−3x⌷xGd2x(MoO4)1−3x(WO4)3x solid solution with limited homogeneity (0<x≤0.25) and cationic vacancies (denoted as ⌷) have successfully prepared by a high-temperature annealing of CdMoO4/Gd2(WO4)3 mixtures composed of 50.00mol% and less of gadolinium tungstate. Initial reactants and obtained ceramic materials were characterized by XRD, simultaneous DTA–TG, and SEM techniques. A phase diagram of the pseudobinary CdMoO4–Gd2(WO4)3 system was constructed. The eutectic point corresponds to 1404±5K and ~70.00mol% of gadolinium tungstate in an initial CdMoO4/Gd2(WO4)3 mixture. With decreasing of Gd3+ content in a CdMoO4 framework, the melting point of Cd1−3x⌷xGd2x(MoO4)1−3x(WO4)3x increases from 1406 (x=0.25) to 1419K (x=0.0833), and next decreases to 1408K (x=0). EPR method was used to identify paramagnetic Gd3+ centers in Cd1−3x⌷xGd2x(MoO4)1−3x(WO4)3x for different values of x parameter as well as to select biphasic samples containing both Cd0.25⌷0.25Gd0.50(MoO4)0.25(WO4)0.75 and Gd2(WO4)3.