SYNTHESIS AND TRANSPORT-PROPERTIES OF LA2-XSRXCUO4 THIN-FILMS DEPOSITED BY LASER ABLATION

Abstract

La2-xSrxCuO4 high-T(c) thin films are fabricated in situ using second harmonics of a pulsed Nd:YAG laser. Effects of the growth parameters, such as substrate temperature and oxygen pressure, on the physical properties of the films are investigated with resistance and X-ray diffractometry measurements. The films deposited on SrTiO3 (100) and MgO (100) substrates have zero resistance transition temperatures around 22 K. Most grains in these films are aligned with their c-axes perpendicular to the substrates. The current-voltage (I-V) characteristics of a patterned La2-xSrxCuO4 thin film are measured at various temperatures near T(c). From the I-V characteristic curves, it is found that the measured critical current density (J(c)) follows a power law J(c) is-proportional-to (1-T/T(c))n with n approximately 1.5. Also, the behaviors of the I-V curves are discussed in terms of the scaling theory of the vortex-glass model.