Reversible in situ modulation of competing phases in manganite/ferroelectrics heterostructures

Department of Physics, The University of Hong Kong - Pokfulam Road, Hong Kong

^a jugao@hku.hk

Received: 3 September 2010
Accepted: 27 January 2011

Abstract

Manganite/ferroelectrics heterostructures were formed by growing a La_0.8Ca_0.2MnO₃ film on single crystal of ferroelectric 0.72Pb(Mg_1/3Nb_2/3)O₃-0.28PbTiO₃ (PMN-PT). In such heterostructures, the lattice strain can be well controlled by the electric field applied to PMN-PT. Thus the properties of the La_0.8Ca_0.2MnO₃ layer become tunable. Significant modulations on both insulator-metal (I-M) phase transition and resistivity (∼15%) were achieved under a field of 8 kV/cm. The compression of the manganite lattice in the (a,b)-plane resulted in a lower resistance and higher I-M transition temperature, demonstrating an enhanced ferromagnetic-metallic phase. Such a modulation of competing phases was ascribed to the distortion of the MnO₆ octahedron.