Magneto-capacitance effects in epitaxial TbMn2O5 thin films

Abstract

Thin films of TbMn2O5 (TMO) were grown on Nb-doped TiO2 (110) substrates by using pulsed laser deposition to investigate the effects of substrate-induced strains on the multiferroic properties observed in the bulk phase. The epitaxial qualities of the films were confirmed by using X-ray azimuthal angle scans of the TMO (201) and the TiO2 (111) reflections. TMO films were magnetically ordered at temperatures below T (N) a parts per thousand 43 K, consistent with the value observed in the bulk. A maximum negative magneto-capacitance effect of about 10% at 8 T was detected near 16 K, where the dielectric constant changed rapidly with a step-like anomaly. Magnetization-induced ferroelectric phases in the epitaxial thin films appear to become destabilized at temperatures below T (N) due to substrate-induced tensile strains causing a weakening of the magnetic exchange interactions.