渠道火花烧蚀法制备La_(0.7)Sr_(0.3)MnO_3薄膜

Preparation of La_(0.7)Sr_(0.3)MnO_3 thin films by channel spark ablation

采用新型渠道火花烧蚀技术在LaAlO3(001)基片上生长了La0.7Sr0.3MnO3(LSMO)薄膜。X射线衍射对样品结构的分析表明,制备的LSMO薄膜具有c轴取向生长的特点,薄膜与基片间因晶格不匹配而受面内应力挤压,发生弛豫而出现两相。在室温下采用振动样品磁强计测试样品的面内方向磁滞回线,表明制备的LSMO样品具有软磁性,矫顽力Hc=13Oe。通过标准四探针法测量了LSMO薄膜的室温薄膜电阻与外加磁场的关系,得知零场电阻率ρ(0)=19.4 mΩ.cm,室温下4800Oe外场作用下的磁电阻变化率为2.25%,对此用双交换作用机制定性地加以了解释。

La0.TSr0.3MnO3 （LSMO） thin films were deposited on LaA103 （LAO） （001） by means of channel spark ablation. X - ray diffraction pattern shows that the LSMO thin films are highly c - axis oriented. The lattice mismatch between LSMO and LAO has compressive strain in - plane and stretching the lattice along c - axis, which resulting in appearence of two phases in the sample. The magnetic hysteresis and electric resistance were investigated by a VSM magnetometer and the standard four probe measurement, respectively. At room temperature the film has characteristics of a soft magnet with a coercivity of 13 Oe. The zero- field resistivity p （0） is 19.4 mΩ·cm and the magnetoresistance value under 4800 Oe at T = 305 K is 2.25 %. Double exchange mechanism is used to qualitatively account for the magnetoresistance effect.