Structural, magnetic and magnetodielectric study in the layered oxide BiPbSr2MnO6

Abstract

Layered oxide BiPbSr2MnO6 (BPSMO) is investigated from structural, magnetic and magnetodielectric perspective. Room temperature Rietveld refinement of neutron powder diffraction pattern shows that the compound crystallizes in orthorhombic ‘Amaa’ structure. Along with an antiferromagnetic ordering (TN) at 190 K, a weak ferromagnetic component is substantiated from magnetization isotherm measured at 175 K as well as temperature dependent neutron powder diffraction. Magnetic reflections were indexed in the nuclear lattice with propagation vector k = (0, 0, 0). Rietveld refinement of powder pattern at 2.8 K demonstrates that magnetic moments are almost normal to the a–b plane in an antiferromagnetic arrangement, but are canted slightly towards a–b plane. The Jahn–Teller distortion shows a substantial increase in the ordered state with decrease in temperature while the variation is trifling above the ordering temperature. The dielectric measurement shows a contrasting nature of the dielectric data for temperatures below and above TN, thus hinting a plausible magnetodielectric (MD) coupling. A confirmation to this coupling is seen in the temperature and field dependent magnetodielectric (MD) results. Substantial MD effect of ~ − 2% is observed at 175 K, near to the vicinity of magnetic transition.