缺氧YBCO的c方向电荷动力学  

C-AXIS CHARGE DYNAMICS IN UNDERDOPED YBa_2Cu_3O_(7-δ)

作　　者：邱祥冈[1] 陈桂香[1] 葛玉建[2] 毕聪志[3] 赵柏儒1 

机构地区：[1]中国科学院物理研究所国家超导重点实验室,北京100080 [2]吉林大学物理系 [3]武汉大学物理系

出　　处：《低温物理学报》2003年第A01期172-176,共5页Low Temperature Physical Letters

摘　　要：我们利用激光沉积法在斜切的钛酸锶基片上制备了缺氧 (1 1 0 )取向的YBa2 Cu3 O7-δ薄膜 .由于在这种薄膜中的c轴躺在基片的表面上 ,从而为我们研究沿c方向的某些独特的物理性质提供了便利 .在这里我们报道了所测量的在不同温度及磁场下这种薄膜沿c方向的远红外偏振反射谱 .结果表明在温度Tc 以上 ,沿c方向运动的载流子浓度很低 .由于载流子之间弱的相干性以及较大的热涨落 ,反射边得到展宽 .随着超导的出现 ,沿着c方向运动的载流子之间的相干性得到加强 ,这表现为一个在 1 0 0波数附近等离子体边的出现 .磁场下的测量表明磁场对等离子体边的位置影响很小 ,这种现象与已有的理论预言不相符合 ,我们认为导致这种现象的原因是超导体中磁通涡旋的钉扎作用 .Oxygen deficient (110) YBa-2Cu-3O-{7-δ} thin films have fabricated by pulsed laser deposition on vicinal (110) SrTiO-3 substrates. Because the c-axis lying in the film in this kind of thin films, it is possible for us to study the c-axis properties of YBa-2Cu-3O-{7-δ}. We have studied the c-axis charge dynamics by far infrared reflectivity measurements on these films. It is shown that above T-c, the free carrier density is very low and it behaves like a bad metal along the c-axis. Upon the appearance of superconductivity, the coherence among the charge carriers builds up. As a result, a reflectivity edge associated with the Josephosn plasma shows up at around 100cm{-1}. We have also studied the influence of magnetic field on the Josephson plasma edge, no significant effect is obtained. A possible reason for this could be the intrinsic pinning associated with the layered structure of YBa-2Cu-3O-{7-δ}.

关 键 词：高温超导 激光沉积法 钛酸锶基片 缺氧取向 YBCO超导薄膜 c轴电荷动力学 远红外偏振反射谱 临界温度 载流子浓度 磁通涡旋钉扎 

分 类 号：O484[理学—固体物理]