INSITU GROWTH AND PROPERTIES OF SINGLE-CRYSTALLINE-LIKE LA2-XSRXCUO4 EPITAXIAL-FILMS BY OFF-AXIS SPUTTERING

Excellent quality La2-xSrxCuO4 epitaxial films of 0.07 less-than-or-equal-to x less-than-or-equal-to 0.34 in (001) and (103) orientations have been successfully grown in situ on SrTiO3, LaAlO3, and Y-stabilized ZrO2 substrates using 90-degrees off-axis sputtering. A record low ion channeling minimal yield chi-min of 1.9% is observed for the first time, and a chi-min of 3% is routinely attained. The surface exhibits a featureless morphology under high-resolution scanning electron microscope, suggesting a roughness less-than-or-equal-to 30-40 angstrom. Superconductivity is maximized at Sr = 0.15 with a typical T(c) (R = 0) of 35 K, a J(c) (4.2 K) of 1-3 X 10(6) A/cm2, and a normal state resistivity two to three times lower than single crystals. T(c) shows a marked reduction with thickness, and the results are interpreted on the basis of partially relieved strained-layer growth coupled with a sensitive dependence of T(c) on uniaxial stress.