Temperature dependence of the ferroelectric and dielectric properties of the Ba0.5Sr0.5TiO3/La0.67Sr0.33MnO3 heterostructure

A ferroelectric and colossal-magnetoresistant material with a Ba0.5Sr0.5TiO3 (BST)/La0.67Sr0.33 MnO3 (LSMO) heterostructure was deposited epitaxially on (001) LaAlO3 substrates through pulsed laser deposition. Measurements of the magnetic and ferroelectric properties show no obvious degradation of the LSMO layer after BST film deposition. For the BST film, as the temperature decreases from 300 to 20 K, both the remanent polarization and the coercive field increase monotonously up to 5.7 muC cm-2 and 63.7 kV cm-1, respectively. Meanwhile, the temperature dependence of the spontaneous polarization shows a second-order ferroelectric phase transition, and the Curie temperature is estimated to be about 220 K. Furthermore, in the temperature range from 20 to 300 K, the dielectric constant (E = 0) and the dielectric tunability (E = 200 kV cm-1) exhibit similar temperature dependences, and show maximum values of 1252 and 45.3% at 200 K, respectively.