In-situ strain effect on extrinsic transport of polycrystalline La 0.7 (Ca,Sr) 0.3 MnO 3 films

The spin-polarised transport in ferromagnetic polycrystalline La0.7(Sr,Ca)0.3MnO3 films on piezoelectric substrate has been investigated. The systematic study involved in finding the effect of in-situ strain on extrinsic electrical transport of various thick polycrystalline La0.7(Sr,Ca)0.3MnO3 thin films. The in-situ strain in the manganite polycrystalline thin film is achieved by applying an electric field to the piezoelectric substrate 0.72 Pb(Mg1/3Nb2/3)O3–0.28 PbTiO3 (PMN-PT). A reversible strain of about 0.11% is acquired with an application of 10kV/cm to the piezoelectric substrate. A typical drop in resistance at low magnetic fields has been found in all the polycrystalline manganite films. The effect of reversible strain versus the resultant strain gauges was discussed in all the polycrystalline films. At low temperatures, the effect of strain on low-field magnetoresistance and high-field magnetoresistance was found to be negligible. Further, the results are compared with the transport in manganite films deposited on step edge junctions.