Microwave Dependence of a-Axis Oriented YBa2Cu3O7 Thin Film
Microwave Dependence of a-Axis Oriented YBa2Cu3O7 Thin Film
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a 轴取向 YBa2Cu3O7 薄膜的微波依赖性
DOI：
10.1109/tasc.2010.2087310
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
S.-J. Kim
中科院分区：
文献类型：
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作者：
S. Saini;M. Takamura;M. Mukaida;S.-J. Kim
采用脉冲激光沉积技术在SrLaGaO 4（100）衬底上生长了a轴取向的YBa 2Cu 3 O 7薄膜。Y-123薄膜的厚度约为500 nm。本征约瑟夫森结（CuO 2平面）在薄膜中垂直于衬底排列。利用聚焦离子束铣削技术制作了桥式图形，使得电流在薄膜中沿着轴向流动。桥的尺寸沿轴向沿着为1 μm，沿b轴向沿着为5 μm。电阻-温度特性曲线表明，转变温度约为89 K。在10 K时，由电流-电压特性曲线测得其临界电流密度（Jc）为2× 106 A/cm 2。用20 GHz的外微波辐照样品，Jc随功率的增加而降低。Jc的这种抑制表明形成了强耦合的层状结构。在微波辐照下，I-V特性曲线出现电压阶跃。电压阶跃的值是不规则的，并随着功率的增加而变化。我们还研究了YBa_2Cu_3 O_7（Y_（123））和PrBa_2Cu_3 O_7（Pr_（123））的全轴取向多层膜。我们制作了一个亚微米的堆栈，其中约瑟夫森结形成的Y123和Pr 123。亚微米叠层对不同频率和功率的微波辐射有响应。详细讨论了这些薄膜的输运特性。
Thea-axis oriented YBa2Cu3O7thin films were grown on SrLaGaO4(100) substrate with a buffer layer of 50 nm thick Gd2CuO4using pulsed laser deposition technique. The thickness of Y-123 thin film was about 500 nm. Intrinsic Josephson junctions (CuO2planes) were aligned perpendicular to the substrate in the thin films. The bridge type pattern was fabricated using focused ion beam milling technique in such a way so that the current flow along thec-axis in thin film. The dimensions of bridge were 1 μm in length along thec-axis and 5 μm in width along the b-axis. The resistance vs. temperature characteristics showed transition temperature of about 89 K. The critical current density (Jc) of 2×106A/cm2was measured from current-voltage (I-V) characteristics at 10 K. The samples were irradiated with external microwave at 20 GHz and the Jcwas suppressed with increase in power. This suppression in Jcindicates the formation of layered structure with strong coupling. The voltage steps were appeared with microwave irradiation in I-V characteristics. The values of voltage steps were irregular and change with increase in power. We have also studied alla-axis oriented multilayered thin films of YBa2Cu3O7(Y123) and PrBa2Cu3O7(Pr123). We fabricated a submicron stack in which Josephson junctions were forming by Y123 and Pr123. The submicron stack showed response with microwave irradiation of different frequency and power. The transport characteristics of these thin films are discussed in detail.