Magnetic and Electrical Characteristics of Nd³⁺-Doped Lead Molybdato-Tungstate Single Crystals

Single crystals of Pb1-3x square(x)25af;Nd-x(2x)(MoO4)(1-3x)(WO4)(3x) (PNMWO) with scheelite-type structure, where square denotes cationic vacancies, have been successfully grown by the Czochralski method in air and under 1 MPa. This paper presents the results of structural, optical, magnetic and electrical, as well as the broadband dielectric spectroscopy measurements of PNMWO single crystals. Research has shown that replacing diamagnetic Pb2+ ions with paramagnetic Nd3+ ones, with a content not exceeding 0.01 and possessing a screened 4f-shell, revealed a significant effect of orbital diamagnetism and Van Vleck's paramagnetism, n-type electrical conductivity with an activation energy of 0.7 eV in the intrinsic area, a strong increase of the power factor above room temperature for a crystal with x = 0.005, constant dielectric value (similar to 30) and loss tangent (similar to 0.01) up to room temperature. The Fermi energy (similar to 0.04 eV) and the Fermi temperature (similar to 500 K) determined from the diffusion component of thermopower showed shallow donor levels.