Pulsed laser deposition as a materials research tool

Pulsed laser deposition PLD.is currently being used to deposit a variety of multicomponent electronic ceramic thin films as a materials research tool for the development of next generation electronic devices. Examples include YBa2Cu3O7ydrferromagnetic multilayers, ferroelectrics and rare earth doped manganite thin films. In YBa2Cu3O7ydrferromagnetic multilayers, the injection of spin-polarized electrons from the ferromagnetic material into the superconductor produces a local reduction in the superconducting order parameter. This effect is being used to develop HTS-based digital logic. The electric field effect in Sr Ba TiO thin films is being used to develop tunable microwave circuits. A 4 : 1 x 1yx . 3 change in the dielectric constant has been observed for fields F80 kVrcm. Microstructural defects associated with cation and anion vacancies have been observed in Sr Ba TiO films. These defects have been correlated with dielectric loss x 1yx . 3 and can be reduced by the use of a compensated targets and a post-deposition anneal of the deposited films. A large temperature coefficient of resistance TCR.has been observed in rare earth doped manganite thin films. A TCR as large as ;30% has been observed for well annealed La0.67Ca0.33MnOd thin films. These materials can be used to increase the sensitivity of uncooled IR focal plane arrays by more than an order of magnitude making them comparable to HgCdTe detectors. This paper presents the advances in thin film processing and the importance of PLD as a tool for research in the physics of thin films, materials science and the fabrication of devices based on electronic ceramics. q1998 Elsevier Science B.V