The effect of strained Si1−xGex and Si1−yCy layers for La0.75Sr0.25MnO3 films grown on oxide-buffered Si substrates

We report the effect of strain on the structural and electrical properties of colossal magnetoresistive (CMR) La0.75Sr0.25MnO3 (LSMO) films grown on Bi4Ti3O12∕CeO2∕ yttrium-stabilized-zirconia-buffered Si1−xGex∕Si(x=0–0.20) and Si1−yCy∕Si(y=0–0.01) substrates. The strain in the buffer layer stack was tailored by varying the Ge and C contents in SiGe and SiC layers. It has been demonstrated that the relaxation of Bi4Ti3O12 layer is dependent on Ge content and this strongly affects the quality of the LSMO film. The surface roughness of LSMO was also strain dependent and samples grown on SiGe and SiC template layers were significantly smoother than that on Si. High resistivity and low values of the temperature coefficient of resistivity were obtained in LSMO films on Si0.8Ge0.2∕Si and Si0.99C0.01∕Si whereas Si0.9Ge0.1∕Si sample shows a slight improvement in the crystalline and electrical LSMO properties compared to the CMR film grown onto the Si substrate.