Deposition-Temperature Dependence of Vortex Pinning Property in YBA2Cu3O7+BaHfO3 Films

Improvement of critical current density (J(c)) in magnetic fields is required in YBa2Cu3O7 films, and process parameters should be optimized for controlling pinning centers. In the present study, a deposition temperature was varied in pulsed laser deposition of YBa2Cu3O7+BaHfO3 films to control the nanorod structure, and its influence on 4 was analyzed. The YBa2Cu3O7 BaHPO3 film deposited at 850 C exhibited pinning force maximum (F-p,F-max) as high as 413 GN/m(3) at 40 K, while the F-p,F-max for the deposition temperature of 850 degrees C at 77K was smaller than that in the YBa2Cu3O7+BaHfO3 film deposited at 900 degrees C. A critical temperature decreased and matching field increased with decreasing the deposition temperature. Increase in deposition temperature is effective in improving the Fp,, in high temperatures, since the critical temperature and matching field dependences of.4 value dominate the F-p,F-max On the other hand, low deposition temperature improves the F-p,F-max in low temperatures since the Fp shift in accordance with matching field is dominant to the F-p,F-max. Thus, the deposition temperature should be set in pulsed laser deposition of YBa2Cu3O7 films containing nanorods considering the J, variation with critical temperature and matching field.