Intrinsic dead layer effects in relaxed epitaxial BaTiO3 thin film grown by pulsed laser deposition

Publication date: 15 May 2017
Source:Materials & Design, Volume 122
Author(s): Y. Gagou, J. Belhadi, B. Asbani, M. El Marssi, J.-L. Dellis, Yu. I. Yuzyuk, I.P. Raevski, J.F. Scott
Epitaxial BaTiO3 (BT) thin film of about 400nm thickness was grown on LaSr0.5Co0.5O3 (LSCO) coated (001)MgO using pulsed laser deposition. Ferroelectric properties of the BT thin film in Pt/BT/LSCO/MgO heterostructure capacitor configuration were investigated. Dynamic P-E hysteresis loops at room temperature showed ferroelectric behavior with Ps=32μC/cm², Pr=14μC/cm² and EC=65kV/cm. Static C-V measurements confirmed reversible switching with a coercive field EC=15kV/cm. Basing on a model taking into account an interface dead-layer we show that the capacitance-voltage "butterfly" loops imply only 25% switching of dipoles that inferred from dynamic polarization-field loops (~4 and ~16kV/cm, respectively). Dielectric permittivity as a function of temperature revealed a first-order ferroelectric-to-paraelectric (FE-PE) phase transition in the BT film characterized by a maximum at TC~130°C. The very large (~126K at 1kHz) difference between TC and the extrapolated Curie-Weiss temperature T0 is attributed to the dead-layer effects.

Graphical abstract

http://ift.tt/2ncrxm7