钙钛矿La2/3Ca1/3MnO3/YBa2Cu4O8/La2/3Ca1/3MnO3三层薄膜的磁输运性能

高温超导材料YBa2Cu4O8(YBCO)和铁磁材料La2／3Ca1／3MnO3(LCMO)形成的三层薄膜LCMO／YBCO／LCMO由对靶溅射技术制得．与YBCO单层薄膜相比，由于超导／铁磁系统中的磁性邻近效应，三层薄膜表现出较低的超导转变温度(Tc,ON)．与LCMO单层膜相比，三层薄膜的金属半导体转变温度(TMS)被提高并且强烈依赖于YBCO层的厚度．随中间层厚度的变化，磁电阻显示出非单调行为，长振荡周期被发现．结果表明，当YBCO处于正常态时两层LCMO膜之间存左着磁性自旋相互作用．

Magnetictransport Properties of Perovskite La2/3Ca1/3MnO3/YBa2Cu4O8/La2/3Ca1/3MnO3 Trilayer Films

Trilayer films in which a superconducting YBa2Cu4O8 (YBCO) layer is sandwiched between two ferromagnetic La2/3Ca1/3MnO3 (LCMO) layers are formed by facing-target sputtering technique. The difference of superconducting transition temperature (TC,ON) between YBCO single layer and LCMO/YBCO/LCMO trilayers as functions of YBCO thickness is described by the magnetic proximity effect in superconductor/ferromagnet structure. In contrast to that for LCMO films,the metal-semiconductor transition temperature (TMS) for LCMO/YBCO/LCMO films is enhanced and strongly depends on the YBCO layer thickness. The magnetoresistance (MR) ratio shows a non-monotonic behavior and a long oscillatory period is found. These results imply that the magnetic spin interaction between the two LCMO layers may exist through the normal-conductive YBCO layer.