Magneto-dielectric signature of Gd 3+ -substituted PbMg 1/3 Nb 2/3 O 3 ceramics

The compound lead magnesium niobate (PMN) is a well-known relaxor ferroelectric depicting frequency-dependent dielectric maximum below ~ 250 K. The temperature and field dependences of ac/dc magnetization reveal magneto-dielectric signatures in Gd-doped PMN ceramic. The inverse magnetic susceptibility shows deviation from linear behavior on cooling, and ac susceptibility shows peak at ~ 125 K, indicating the formation of local magnetic-interacting areas, which are different from polar clusters formed at higher temperatures. However, low-temperature magnetization versus magnetic field (MH) curve described by all the samples is well elucidated by the Brillouin functions suggesting weak deviations due to some magneto-electric interaction. For higher Gd-doped PMN ( x > 0.05), local interaction between the magnetic polar regions are believed to occur, where both Pb and Mg sites are substituted by Gd ions in the lattice. This result is the first strong evidence of both magnetic and polar interacting regions in this family of materials, where the temperature scales of two phenomena are different. The interaction between the two subsystems via electrostriction and magnetostriction leads to weak magneto-dielectric effect.