CORRELATION BETWEEN HALL NUMBERS AND T-C IN LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.5) THIN-FILMS PREPARED BY RF THERMAL PLASMA DEPOSITION METHOD

The temperature dependence of the resistivity and the Hall coefficient R(H) was measured for Y1-xCaxBa2Cu3O7-delta thin films prepared on Sr TiO3 substrates using the RF thermal plasma deposition method. Transit ion temperature T-c and resistivity of the as-grown film decrease with increasing Ca concentration. However, oxygen treatment affects the tr ansport properties of the films and a slight increase in oxygen defici ency delta increases T-c in heavily Ca-doped samples through changes i n the hole density. There is a maximum T-c of about 90 K with variatio n of the carrier density and further reduction of the oxygen content l owers T-c again. The value of the maximum T-c is independent of Ca con centration and a parabolic relationship between Hall number and T-c ex ists in the Y1-xCaxBa2Cu3O7-delta system.