Ej. Cukauskas et al., MORPHOLOGY AND TRANSPORT OF YBA2CU3O7-X SPUTTERED IN ARGON, OXYGEN, AND HYDROGEN - DEPENDENCE ON DEPOSITION TEMPERATURE, Journal of applied physics, 74(11), 1993, pp. 6780-6787
YBa2Cu3O7-x films have been deposited on MgO by reactive, off-axis mag
netron sputtering in an argon, oxygen, and hydrogen gas mixture. The m
aterial and electrical properties of the films were studied for deposi
tion temperatures from 600 to 760-degrees-C. The films, all approximat
ely 300 nm thick, were predominantly a-axis oriented when deposited at
or below 620-degrees-C but were c-axis oriented when deposited at tem
peratures above 640-degrees-C. The surfaces of films deposited between
640 and 710-degrees-C were partially covered with a-axis grains. Surf
ace roughness measurements indicated the smoothest films occurred for
deposition temperatures below 680-degrees-C. Resistance ratios as grea
t as 3.1 were observed for some films. Transition temperatures exceede
d 89 K and resistivities at 100 K were less than 150 muOMEGA cm for th
e best films. Low-temperature critical current densities exceeded 10(7
) A/cm2 for films deposited from 640 to 720-degrees-C. The temperature
dependence of the critical current density near the transition temper
ature had a power law dependence of nearly 3/2 for deposition temperat
ures below 690-degrees-C. The power law dependence decreased for incre
asing deposition temperatures, dropping to nearly 1.1 in the film depo
sited at 750-degrees-C.