The effect of strained Si_(1-x)Ge_x and Si_(1-y)C_y layers for La_(0.75)Sr_(0.25)MnO_3 films grown on oxide-buffered Si substrates

摘要

We report the effect of strain on the structural and electrical properties of colossal magneto-resistive (CMR) La_(0.75)Sr_(0.25)MnO_3 (LSMO) films grown on Bi_4Ti_3O_(12)/CeO_2/ yttrium-stabilized-zirconia-buffered Si_(1-x)Ge_x/Si (x = 0-0.20) and Si_(1-y)C_y/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 Bi_4Ti_3O_(12) 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 Si_(0.8)Ge_(0.2)/Si and Si_(0.99)C_(0.01)/Si whereas Si_(0.9)Ge_(0.1)/Si sample shows a slight improvement in the crystalline and electrical LSMO properties compared to the CMR film grown onto the Si substrate.