Superconducting and electro-optical thin films prepared by pulsed laser deposition technique

The pulsed laser deposition (PLD) technique is an excellent method to prepa re single crystalline complex oxide thin films. We have successfully grown films for the use in HTS SQUID-devices as well as for thin film optical wav eguides. The Josephson junction used in the HTS SQUIDs is formed by a step edge type gain boundary junction. The step preparation is a very critical p rocess in the SQUID preparation to achieve reproducible low 1/f noise devic es. We have established a new ion beam etching process to achieve clean and steep edges in LaAlO3 (100) substrates. The 1/f noise of SQUIDs prepared w ith the new method is drastically reduced. In the process of developing thi n film electro-optical waveguide modulators we investigated the influence o f different substrates on the optical and structural properties of epitaxia l BaTiO3 thin films. These films are grown on MgO(1 0 0), MgAl2O4(1 0 0), S rTiO3(1 0 0) and MgO buffered Al2O3(1 (1) over bar 0 2) substrates. The wav eguide losses and the refractive indices were measured with a prism couplin g setup. The optical data are correlated to the results of Rutherford backs cattering spectrometry/ion channeling (RBS/C), X-ray diffraction (XRD), ato mic force microscopy (AFM) and transmission electron microscopy (TEM). The dielectric constant, the ferroelectric hysteresis loop and the transition t emperature (ferroelectric to paraelectric state) of the BaTiO3 thin films a re measured. (C) 2000 Elsevier Science B.V. All rights reserved.