钙钛矿La0.67Pb0.33MnO3薄膜的制备及表征

利用磁控溅射法在单晶LaAlO3(100)衬底上成功的外延生长了La0.67Pb0.33MnO3薄膜。用X射线衍射、原子力和超导量子干涉仪、振动样品磁强计对其进行了表征。结果表明,薄膜为赝立方钙钛矿结构,晶胞参数为a=3.861 nm,具有良好的单晶外延结构和光滑的表面。居里温度TC=345 K,在居里温度附近,发生铁磁-顺磁转变。此材料呈现出一种典型的自旋玻璃特性,是由于应力造成的。在室温条件下,当H=0.8T时,磁电阻效应非常明显,此现象是由于固有磁电阻效应引起的,并不是低场磁电阻效应引起的。室温下,其矫顽力只有50奥斯特。

Fabrication and characterization of perovskite-type La0.67Pb0.33MnO3 thin film

Using magnetron sputtering method,La0.67Pb0.33MnO3 thin films have been grown on(100)LaAlO3 single-crystal substrates.The thin film was characterized by X ray diffraction,atomic force microscopy,superconducting quantum interference device and vibrating sample magnetoments.The results show that the thin film have a pseudo-cubic perovskite structure with the cell parameter a=3.861nm,have a good epitaxial direction and smooth surface.The Curie temperature is 345 K,near the Curie temperature,the magnetic property shows a transition from ferromagnetic to paramagnetic.La0.67Pb0.33MnO3 thin film indicates a characteristic spin glass from zero-field cooled and field cooled magnetization curve,which is due to strain effects.The thin film have quite a distinctive magnetoresistance effect at the room temperature when the magnetic field is 0.8T,which implies the CMR effect in La0.67Pb0.33MnO3 films originates only from the intrinsic MR effect instead of low-field magnetoresistance effect.The coercive force of the thin film is only 50Oe at the room temperature.