paper

Large magnetocapacitance in electronic ferroelectric manganite systems

arXiv:1311.0673 · doi:10.1063/1.4831944

Abstract

We have observed a sizable positive magnetocapacitance ( $\sim$ $5 - 90%$ ) in perovskite Pr $_{0.55}$ Ca $_{0.45}$ MnO $_{3}$ and bilayer Pr(Sr $_{0.1}$ Ca $_{0.9}$ ) $_{2}$ Mn $_{2}$ O $_{7}$ system under 5T magnetic field across 20-100 K below the magnetic transition point T $_{N}$ . The magnetodielectric effect, on the other hand, exhibits a crossover: (a) from positive to negative for the perovskite system and (b) from negative to positive for the bilayer system over the same temperature range. The bilayer Pr(Sr $_{0.1}$ Ca $_{0.9}$ ) $_{2}$ Mn $_{2}$ O $_{7}$ system exhibits a sizable anisotropy as well. We have also noticed the influence of magnetic field on the dielectric relaxation characteristics of these systems. These systems belong to a class of improper ferroelectrics and are expected to exhibit charge/orbital order driven ferroelectric polarization below the transition point T $_{C O}$ . Large magnetocapacitance in these systems shows typical multiferroic behavior even though the ferroelectric polarization is small in comparison to that of other ferroelectrics.

6 pages with 5 embedded figures; accepted for publication in J. Appl. Phys