Influence of different substrates on phase separation in $La1−x−yPryCaxMnO3$ thin films

Large scale phase separation between ferromagnetic metallic and charge-ordered insulating states in $La1−x−yPryCaxMnO3$ (LPCMO) crystals and thin films is very sensitive to structural and magnetic changes and is responsible for the enhanced magnetoresistance in LPCMO compared to its parent compounds. By epitaxially growing LPCMO thin films on different substrates, the strain on the LPCMO thin films can be changed, thereby controlling the energy balance between the two phases. LPCMO films of several different thicknesses have been grown on $NdGaO3$ (NGO), $SrTiO3$ (STO), $SrLaGaO4$ (SLGO), and $LaAlO3$ (LAO) substrates. The compressive strain from the LAO and SLGO substrates suppresses the long-range charge ordering in these samples and enhances magnetoresistance and magnetic hystereses. Conversely, the tensile strain from the STO and NGO substrates enhances the long-range charge ordering and reduces the magnetoresistance and magnetic hystereses.