Versatility Of Pulsed Laser Deposition Technique For Preparation Of High Tc Superconducting Thin Films

Abstract

Pulsed laser deposition (PLD) from a single target is simple, easy, and inexpensive compared to most of the other techniques employed for preparation of high Tc superconducting thin films. We present the results of Rutherford Backscattering study of the PLD process and identify the parameters which are critical in controlling the deposited film stoichiometry. Also, by using mass spectrometry the nature of the laser deposition process has been investigated. The PLD technique enables us to get films with stoichiometry close to that of the target. High Tc superconducting thin films of R-Ba-Cu oxide (R,Y, Eu, Gd, Sm, Tm, Er) have been prepared using PLD. Films deposited in vacuum at 450 C were not superconducting and post-annealing at over 850 C in oxygen was necessary to achieve high zero resistance temperatures. Detailed analyses of the films were carried out using RBS, TEM, XRD, Raman, Auger, SIMS, X-ray absorption and resistivity measurements. Recently, we were able to obtain superconducting thin films of Y-Ba-Cu Oxide with zero resistance temperature over 80 K at and below 650 C (processing temperature). The critical current densities in the films prepared at low temperature on SrTiO3 were on the order of 5x105 A/cm2 at 77 K. These films exhibited minimal interface reaction and were very smooth. We will also show that PLD can be utilized to prepare high Te superconducting thin films of Bi-Sr-Ca-Cu oxide.