Preparation of thin film high temperature superconductors

Abstract

Fundamental issues in pre aring high quality high T YBa&u,O thin films are adgessed. The techniques of inverted q%idrical magnetron sputtering and pulsed laser deposition are chosen as successful examples to illustrate how the key problems can be solved. The fabrication of YBa2(3l,O,$PrBa;?Cu307-su erlattices where superconductivity in a singfe unit celrlayer of YB Cu30 -x was observed demonstrates the state of the art of%in fi6n deposition of high T, materials. Systematic variations of the deposition parameters result in changes of superconducting and structural properties of the films that correlate with their microwave and infrared characteristics.

YBaCuO thin films on sapphire up to 2-inch-diameter for microwave applications

“…As we can see, the chemical composition of particles is Cu primary (note, that the oxygen-line is absent in the spectrum). Our surface morphology data are well in accord, in particular, with the results of [5] for YBCO on SrTiO3 and LaAl03 sputtered films. The contact region of the particles to the film surface is an a-& oriented YBCO grain [5].…”

“…Our surface morphology data are well in accord, in particular, with the results of [5] for YBCO on SrTiO3 and LaAl03 sputtered films. The contact region of the particles to the film surface is an a-& oriented YBCO grain [5]. Because the volume of the a-axis oriented grains in the film decreases with increase of Td as shown in Fig.2 the particles density decrease also.…”

Advances in the growth and characterization of magnetic, ferroelectric, and multiferroic oxide thin films

“…Key to the ability to create high quality oxide thin films is intimate knowledge of sputtering yields of the various chemical species in a material (as different elements are sputtered at different rates from targets, starting composition may need to be carefully tuned to give stoichiometric final films), deposition rate is key for controlling the crystal phase, temperatures for microstructure, sputtering atmosphere is important in controlling surface structure, and substrate position or bias voltage is key in determining the types and density of defects in these films. Several sputter deposition techniques have been used in the growth of oxide thin films including on-axis dc magnetron sputtering [51], cylindrical magnetron sputtering [52], ion-beam sputtering [53], and off-axis sputtering [54]. Of particular interest for the growth of oxide thin films is the use of a reactive gas -such as pure O 2 or Ar/O 2 mixtures -which helps assure oxygen stoichiometry is close to the desired level.…”

Ultrathin Ferroelectric Films: Growth, Characterization, Physics and Applications

“…There are several types of sputtering techniques, depending on how the flux of energetic particles that bombards the target surface is created, the kinetic-energy range of the bombarding particles, and the geometry of the system [11], such as on-axis dc magnetron sputtering [79], cylindrical magnetron sputtering [80], off-axis sputtering [81], and ion-beam sputtering [82]. Among them, magnetron sputtering is most widely used.…”