Hetero-Epitaxial Growth of YBCO and MgB 2 Thin Films on Decorated Substrates with Nano-Wires and Nano-Particles
Hetero-Epitaxial Growth of YBCO and MgB 2 Thin Films on Decorated Substrates with Nano-Wires and Nano-Particles
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纳米线和纳米颗粒装饰基底上异质外延生长YBCO和MgB 2 薄膜
DOI：
10.1557/opl.2012.1485
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
S. Ohshima
中科院分区：
文献类型：
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作者：
S. Ohshima
超导NMR拾取线圈必须在高磁场下具有低表面电阻（Rs）。降低超导薄膜的Rs的一种方法是在薄膜中加入人工钉。我们研究了MgB 2和YBCO薄膜的异质外延生长的装饰蓝宝石和MgO衬底上，同时使用纳米线和纳米颗粒添加引脚的薄膜。利用ZnO纳米线在MgB 2薄膜中添加人工晶界钉。具有纳米台阶边缘的倾斜c-平面蓝宝石衬底用于这些衬底。通过改变倾斜角度，可以控制具有一个晶格台阶边缘的平台宽度。AFM图像显示，倾斜的c面蓝宝石衬底具有直的纳米台阶边缘。采用MOCVD方法在纳米台阶边缘修饰ZnO纳米线，然后在MgB 2薄膜上溅射沉积ZnO纳米线。然后用蓝宝石棒谐振器测量膜的Rs。在高磁场下，在倾斜c面蓝宝石衬底上制备的MgB 2薄膜的Rs值低于在常规蓝宝石衬底上制备的MgB 2薄膜的Rs值。采用BaZrO 3（BZO）纳米粒子作为人工钉扎剂，对YBCO薄膜进行了人工钉扎。采用激光沉积法在MgO衬底上制备了BZO纳米粒子。这些颗粒的尺寸和密度由激光脉冲数控制。采用激光沉积法在修饰的MgO衬底上制备了YBCO薄膜。在强磁场下，修饰后的MgO衬底上的YBCO薄膜的Rs值低于常规MgO衬底上的YBCO薄膜的Rs值。我们阐明了在MgB 2和YBCO薄膜中的人工钉扎对于降低高磁场下的Rs是有用的。
Superconducting NMR pickup coils have to have a low surface resistance (Rs) under a high magnetic field. One way of reducing the Rs of superconducting thin films is adding artificial pins to the films. We examined the hetero-epitaxial growth of MgB 2 and YBCO thin films on decorated sapphire and MgO substrates while using nano-wires and nano-particles to add pins to the films. We used ZnO nano-wire to add artificial grain boundary pins to MgB 2 films. The tilted c-plane sapphire substrate with nano-step edges was used for these substrates. The terrace width with one lattice step edge can be controlled by changing the tilt angle. AFM images showed that the tilted c-plane sapphire substrate had straight nano-step edges. ZnO nono-wires were decorated on the nano-step edges by MOCVD, and then deposited on MgB 2 films by sputtering. The Rs of the films was then measured with a sapphire rod resonator. The Rs of MgB 2 thin films fabricated on the tilted c-plane sapphire substrate with ZnO nano-wires was lower than that of MgB 2 thin films on a conventional sapphire substrate under a high magnetic field. We used BaZrO 3 (BZO) nano-particles to add the artificial pins to YBCO thin films. The BZO particles on the MgO substrates were fabricated by laser deposition. The size and density of these particles were controlled with a pulse number of laser shot. YBCO thin films were formed on decorated MgO substrate by laser deposition. The Rs of YBCO thin films on the decorated MgO substrate was lower than that of the YBCO films formed on a conventional MgO substrate under a high magnetic field. We clarified that artificial pins in MgB 2 and YBCO thin films are useful for decreasing the Rs under a high magnetic field.