Thermal and magnetic properties of new scheelite type Cd_(1-3x)□_xGd_(2x)MoO_4 ceramic materials

摘要

The limited scheelite type Cd_(1-3x)□_xGd_(2x)MoO_4 solid solution, where 0 < x ≤ 0.25 and □ are cationic vacancies have been successfully synthesized by high-temperature annealing of CdMoO_4/Gd_2(MoO_4)_3 mixtures composed of 50.00 mol.% and less of Gd_2(MoO_4)_3. The obtained materials as well as CdMoO_4 and Gd_2(MoO_4)_3 were characterized by powder XRD, DTA-TG, DSC, and SEM techniques. A phase diagram of the pseudobinary CdMoO_4-Gd_2(MoO_4)_3 system was constructed. The eutectic point corresponds to 1350±5 K and ~70.00 mol.% of Gd_2(MoO_4)_3 in an initial CdMoO_4-Gd_2(MoO_4)_3 mixture. With decreasing of Gd~(3+) amount in the crystal lattice of CdMoO_4, a melting point of the Cd_(1-3x)□_xGd_(2x)MoO_4 solid solution increases from 1351 (x=0.25) to 1408 K (x=0). EPR method was used to identify the paramagnetic Gd~(3+)centers in Cd_(1-3x)□_xGd_(2x)MoO_4 for different values of x parameter as well as to select biphasic samples containing both Cd_(0.2500)□_(0.2500)Gd_(0.5000)MoO_4 and Gd_2(MoO_4)_3.