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采用溶胶-凝胶方法在Si(111)上制备了LSMO(x=0.17)薄膜.研究了块体材料和不同厚度薄膜R-T曲线、红外光谱和X射线衍射.结果表明,LSMO薄膜属于正交晶体结构,薄膜取向与膜厚度有关,当膜厚度为450nm或680nm时,主要取向〈200〉,而膜厚度为900nm时取向为〈020〉:根据离子对相互作用能和谐振子模型,得到了红外吸收与Mn—O—Mn键长和键角关系式,600cm-1附近红外吸收与晶格常数b的变化有关;块体与薄膜的金属—绝缘体转变温度(TMI)存在较大差别,薄膜转变温度显著低于块体,并与厚度有一定关系.认为是LSMO薄膜中的应力诱导了晶格常数变化,引起键角改变及JT效应是转变温度变化的主要原因.
LSMO (x = 0.17) thin films were prepared on Si (111) by sol-gel method.The RT curves, infrared spectra and X-ray diffraction of bulk materials and films with different thicknesses were studied.The results show that LSMO films belong to orthorhombic Structure and film orientation are related to the film thickness. The major orientations are <200> when the film thickness is 450 nm or 680 nm, and <020> when the film thickness is 900 nm. According to the ion pair interaction energy and the harmonic oscillator model, the infrared absorption The relationship between the length of Mn-O-Mn bond and the bond angle is related to the change of the infrared absorption near 600cm-1 and the lattice constant b. The metal-insulator transition temperature (TMI) Which is significantly lower than that of the bulk and has a certain relationship with the thickness.It is believed that the stress in the LSMO film induces the change of the lattice constant and the change of the bond angle and the JT effect are the main reasons for the change of the temperature.