Synthesis and transport properties of La_{2 - x}Sr_xCuO₄ thin films deposited by laser ablation

La_{2 - x}Sr_xCuO₄ 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 La_{2 - x}Sr_xCuO₄ 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 ∞ (1 - T/T_c)ⁿ with n ∼ 1.5. Also, the behaviors of the I-V curves are discussed in terms of the scaling theory of the vortex-glass model.