巨大磁気抵抗薄膜の微細構造観察 Observation of Microstructure in Colossal Magnetoresistance Thin Films
We observed the microstructure of perovskite thin films, and compared the results with their colossal magnetoresistance (CMR) properties. Epitaxial or textured films of La<SUB>1-x</SUB>Sr<SUB>x</SUB>Mn<SUB>y</SUB>O<SUB>3-δ</SUB>were prepared by rf sputtering on (100)SrTiO<SUB>3</SUB> and (110)sapphire single crystal substrates. The films were investigated by X-ray diffraction, magnetoresistance measurement, and transmission electron microscopy (TEM). The magnetoresistance of the films deposited on SrTiO<SUB>3</SUB> substrate shows similar temperature dependence to that of bulk single crystals. The temperature dependence of the magnetresistance in the films on a sapphire substrate is different from that in bulk single crystals, that is, the magnetoresistance decrease monotonously with increasing temperature. We revealed by TEM observations that the films on SrTiO<SUB>3</SUB> substrate grew epitaxially with a number of defects, however, the films on sapphire substrate grew with a columnar structure and showed no epitaxy. Therefore, the difference in the MR properties is attributed to the lattice mismatch between films and substrates.
粉体および粉末冶金 46(2), 147-150, 1999-02-15
Japan Society of Powder and Powder Metallurgy