Effect of LaAlO3 Twin-domain Topology on Local DC and Microwave Properties of Cuprate Films
Different imaging modes of low temperature laser scanning microscopy (LTLSM) have been applied to probe local optical and superconducting properties, as well as the spatial variations in thermoelectric and electronic (both dc and rf) transport, in a YBa2Cu3O6.95/LaAlO3 (YBCO/LAO) superconducting microstrip resonator with micron-range resolution. Additionally, the local sources of microwave nonlinearity (NL) were mapped in two-dimensions simultaneously by using the LTLSM in two-tone rf intermodulation distortion contrast mode as a function of (x, y) position of the laser beam perturbation on the sample. The influence of the direction of individual twin-domain YBCO blocks on its NL properties was analyzed in detail. The result shows the direct spatial correlation between NL microwave and dc electronic transport properties of the YBCO film that are imposed by the underlying twin-domain topology of the LAO substrate. In these circumstances, the scale of local NL current densities J(IM)(x, y) in different areas of the YBCO microstrip quantitatively coincide with the scale of local critical current densities J(c)(x, y) measured at the same positions.
Published in: Journal of AppliedPhysics, Volume 108, Issue 3, August 1, 2010. Copyright © 2010 American Institute ofPhysics, Melville, NY. The final published version is available at: http://dx.doi.org/10.1063/1.3467003