Epitaxial growth and magnetic response of La_0.8Ca_0.2MnO₃ thin films grown on ultrathin SrTiO₃ buffered GaAs substrates

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

^a jugao@hku.hk

Received: 21 February 2012
Accepted: 3 April 2012

Abstract

Colossal-magnetoresistance manganites La_0.8Ca_0.2MnO₃ (LCMO) films were epitaxially grown on (001) GaAs substrates by pulsed-laser deposition. An ultrathin SrTiO₃ (STO) film (∼10 nm) was used as a buffer layer to reduce the lattice mismatch and interdiffusion. The crystallinity and the growth mode were investigated using X-ray diffraction and reflective high-energy electron diffraction. The results indicate that LCMO is grown with a highly c-axis epitaxial feature depending on the STO buffer layer. The heterostructures exhibit good rectifying behavior in a wide temperature range from 50 K to 300 K with a paramagnetic-ferromagnetic transition at ∼200 K. Both the LCMO thin films and the LCMO/STO/GaAs heterojunctions showed magnetic response under the magnetic fields.