E. S. Ramakrishnan

Ferroelectric lead zirconate titanate thin films by radio frequency magnetron sputtering

Ferroelectric thin films of lanthanum modified lead zirconate titanate (PLZT) were deposited on platinum and fused quartz substrates by rf magnetron sputtering. Cold pressed powder was used as the target with excess PbO in the target composition. The PLZT films were deposited at different substrate temperatures and the thickness of the sputtered films were in the 1–2 μm range. The effect of post‐deposition anneal on the structure and ferroelectric properties are discussed. The structure and composition of the films were determined by x‐ray diffraction and energy dispersive x‐ray analysis and found to be strongly dependent on the excess PbO content in the target, and on the deposition parameters. Films deposited on platinum have (111) or (110) orientation depending on the deposition temperature and the oxygen content in the sputter gas. Film Pb/(Zr+Ti) ratios were determined from energy dispersive x‐ray spectra as a function of the sputtering geometry. Electrical properties were evaluated in terms of the d...

Synthesis of Z-type hexagonal ferrite films by rf magnetron sputtering techniques (abstract)

The synthesis of textured stoichiometric Z-type hexagonal ferrite films, Ba3Me2Fe24O41 (Me2-Z), where Me is a divalent ion, by sputtering techniques is reported. The compound Co2-Z shows a large planar anisotropy with a high permeability at room temperature, and thus, are promising candidates for microwave device applications. The objective here was to develop thin films of these materials for devices on integrable substrates. The films were deposited on unheated Si substrates by rf magnetron sputtering using oxide targets in a mixed argon/oxygen atmosphere. Studies on the crystal structure, composition, and magnetic properties were performed on 1.6 μm thick films. The films were characterized by x-ray diffraction and scanning electron microscopy, and the composition was analyzed by energy dispersive x-ray analysis and Auger electron spectroscopy/secondary-ion-mass-spectroscopy techniques. As-deposited films were amorphous and paramagnetic. The films were subjected, either to a rapid thermal anneal at 900...

High‐frequency properties of superconducting Y‐Ba‐Cu‐oxide thin films

rf and microwave properties of superconducting YBa2Cu3O7−x thin films were measured and analyzed using a coplanar resonator structure. The films were developed by sequential electron‐beam evaporation of the metals followed by postanneal processing. dc properties of the films were obtained from resistance‐temperature and current‐voltage measurements to evaluate the transition temperature and current densities. High‐frequency properties were measured from 70 to 10 K and in the frequency range 1–3 GHz to determine the film characteristics as compared to pure copper films on the same substrates.