Electrical properties of semiconducting YBa2Cu3O7-x thin film with variation of oxygen partial pressure

Abstract

YBa2Cu3O7-x (YBCO) is the material of choice for second-generation superconducting wires and is the only current option for critical current density (J(c))> 1 MA/cm(2) at 77 K [1]. YBCO belongs to a class of copper oxides well known for their superconducting properties. Its conduction properties can be changed from metallic (0.5 < x < 1) to insulating (0x0.5) by suitably decreasing the oxygen content [2]. The structural, electrical and optical properties of YBa2Cu3O7-x can be varied by adjusting the oxygen content x [3, 4]. As x is decreased to 0.5, the crystal undergoes a phase transition to a tetragonal structure and it exhibits semiconducting conductivity characteristics as it exists in a Fermi glass state. YBCO precursor solutions were prepared by the sol-gel method YBCO films were fabricated by the spin coating method, and structural and its electrical were studied at various oxygen partial pressures. The films Ar/O-2 at 7 : 3 showed the more obvious YBa2Cu3O7-x phase and tetragonal phase. The thickness of all the films was approximately 0.23 similar to 0.31 mu m and the average grain size of the YBCO film Ar/O-2 at 7 : 3 was about 50 nm. Temperature resistance coefficient (TCR), responsivity, and detectivity of the YBCO film Ar/O-2 at 7 : 3 were 3.2%/K at room temperature, 14.72 V/W, and 2.27 cmHz1/2/W, respectively.