脉冲激光沉积La_(1/3)(Ca_(2/3)Sr_(1/3))_(2/3)MnO_3薄膜结构及输运特性的研究  

Study on Structure and Transport Characteristic of La_(1/3)(Ca_(2/3)Sr_(1/3))_(2/3)MnO_3 Thin Film by Pulsed-Laser Deposition

作　　者：王永仓[1] 陈长乐[1] 高国棉[1] 陈钊[1] 李润玲[2] 宋宙模[1] 

机构地区：[1]西北工业大学,陕西西安710072 [2]空军工程大学,陕西西安710052

出　　处：《稀有金属材料与工程》2005年第12期1854-1856,共3页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50331040;60171043);陕西省自然科学基金(2001C21);西北工业大学博士论文创新基金(200242)

摘　　要：采用PLD法在LaAlO_3(012)单晶衬底上外延生长了高、双掺杂La_(1／3)(Ca_(2／3)Sr_(1／3))(2／3)MnO_3(LCSMO)薄膜。薄膜的X射线衍射谱表明,薄膜具有钙钛矿赝立方结构,且具有(012)方向的择优取向；用原子力显微镜对薄膜的表面形貌进行了分析,发现薄膜表面相对比较平坦；在密封的液氮杜瓦瓶里用四探针法对薄膜的输运特性进行了测试,电阻-温度试验曲线表明,在温度77K～400K的范围内薄膜呈现类半导体特性,没有金属-绝缘体转变温度(T_(Ml))出现；薄膜的红外透射谱在606cm^(-1)处有一个很强的吸收峰,由红外透射谱计算出光学能隙E_(opt)大约为0.7eV,薄膜的光学折射率为1.373。分析认为LCSMO薄膜的类半导体特性是由于A离子半径变化引起晶格畸变造成的。Using pulsed-laser deposition method, the heavy and double-doped La1/3（Ca2/3Sr1/3）2/3MnO3 （LCSMO）thin film was epitaxially prepared on LaAIO3 （012） single crystal substrate. The structure of the film studied by X-ray diffractometry shows the film has perovskite pseudocubic structure, and is of preferential orientation （012）. The morphology studied by atomic force microscopy shows the surface of the film is relatively smooth. A transport property of the thin film in a closed-circuit liquid nitrogen cryostat was determined using the four-probe method. The temperature dependence of resistance exhibit a semiconducting behavior, and no metal-insulator transition temperatures TMI of the film in the temperature range of 77 K-400 K. And the infrared transmission spectrum indicates there is a strong absorption peak at k=606cm^-1, and from this the optical energy gap is about 0.7 eV. and the optical refractive index is 1.373. Author suggest these properties are caused by the lattice distortion caused by the different A-site radius.

关 键 词：脉冲激光沉积(PLD) LCSMO薄膜 钙钛矿结构 

分 类 号：O484.1[理学—固体物理]