Preparation, thermal stability and magnetic properties of new AgY1−xGdx(WO4)2 ceramic materials

Polycrystalline samples of α-AgY1−xGdx(WO4)2 with x=0, 0.005, 0.01, 0.025, 0.05, 0.1, 0.2, and 1 have been prepared by a solid state reaction method and the influence of Gd3+ substitution for Y3+ on microstructure, thermal and magnetic properties was investigated. The X-ray diffraction analysis showed the phases to crystallize in the monoclinic symmetry, space group C2/m. A reversible monoclinic to tetragonal phase transition occurs in AgY1−xGdx(WO4)2 and strongly depends on Gd3+ ion concentration. Electron paramagnetic resonance (EPR) spectra of Gd3+ ions showed non-monotonous dependence of interaction strength on gadolinium concentration. Magnetic measurements showed paramagnetic behavior and strong increase of magnetic moment as the yttrium content decreases.