Epitaxial growth and magnetic response of La0.8Ca0.2MnO3 thin films grown on ultrathin SrTiO3 buffered GaAs substrates

Colossal-magnetoresistance manganites La0.8Ca0.2MnO3 (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.