Evidence for multiferroic characteristics in NdCrTiO5

We report NdCrTiO5 to be an unusual multiferroic material with large magnetic field dependent electric polarization. While magneto-electric coupling in this two magnetic sub-lattice oxide is well established, the purpose of this study is to look for spontaneous symmetry breaking at the magnetic transition. The conclusions are based on extensive magnetization, dielectric and polarization measurements around its antiferromagnetic ordering temperature of 18 K. Room temperature X-ray diffraction pattern of NdCrTiO5 reveals that the sample is single phase with an orthorhombic crystal structure that allows linear magneto-electric coupling. DC magnetization measurement shows magnetization downturn at 11 K together with a small kink corresponding to the Cr+3 sub-lattice ordering at ~18 K. An anomaly in dielectric constant is observed around the magnetic ordering temperature that increases substantially with increasing magnetic field. Through detailed pyroelectric current measurements at zero magnetic field, particularly as a function of thermal cycling, we establish that NdCrTiO5 is a genuine multiferroic material that is possibly driven by collinear magneto-striction.