Abstract: Materials of composition La.sub.v X.sub.w M.sub.y Mn.sub.z O.sub.x, with x selected from Mg, Sc, Al, Zn, Cd, In and the rare earths that have an ionic radius smaller than that of La, with M selected from Ca, Sr, Ba and Pb, and with v, w, y, z and x in the ranges 0.45-0.85, 0.01-0.20, 0.20-0.45, 0.7-1.3 and 2.5-3.5, respectively, can have substantially improved magnetoresistance (MR) ratios, as compared to the corresponding X-free comparison material. In particular, the novel materials in polycrystalline (or non-epitaxial thin film) form can have relatively large MR ratios. For instance, polycrystalline La.sub.0.60 Y.sub.0.07 Ca.sub.0.33 MnO.sub.x had a peak MR ratio in excess of 10,000% (in absolute value) in a field of 6 T.

Abstract: This invention is predicated upon applicants' discovery that conventional techniques for minimizing metal loss from sintered ceramic materials are not adequate in the fabrication of small ceramic components such as multilayer monolithic magnetic devices wherein a magnetic core is substantially surrounded by an insulating housing. Applicants have determined that this metal loss problem can be solved by providing the component with a housing layer having an appropriate concentration of metal. Specifically, if the insulating housing material around the magnetic core has, during the high temperature firing, the same partial pressure of metal as the magnetic core material, there is no net loss of metal from the core. In a preferred embodiment, loss of zinc from a MnZn ferrite core is compensated by providing a housing of NiZn ferrite or zinc aluminate with appropriate Zn concentrations. Similar considerations apply to other ceramic components.

Abstract: This invention pertains to a p-i-n In.sub.0.53 Ga.sub.0.47 As photodiode having an optically transparent composite top electrode consisting of a thin semitransparent metal layer from 10 to 40 nm thick and a transparent cadmium tin oxide (CTO) layer from 90 to 600 nm thick. The metal layer makes a non-alloyed ohmic contact to the semiconductor surface, acts as a barrier between the semiconductor and the CTO preventing oxidation of the semiconductor from the O.sub.2 in the plasma during reactive magnetron sputtering of the CTO layer, and prevents formation of a p-n junction between the semiconductor and CTO. The CTO functions as the n or p contact, an optical window and an anti-reflection coating. The top electrode also avoids shadowing of the active layer by the top electrode, thus allowing greater collection of incident light. Since the top electrode is non-alloyed, inter-diffusion into the i-region is not relevant, which avoids an increased dark current.

Abstract: Optically transparent and electrically conductive cadmium tin oxide or indium tin oxide is employed in vertical cavity surface emitting lasers for vertical current injection. Continuous wave lasing at room temperature is achieved in GaAs/AlGaAs quantum well lasers. Devices with a 10 .mu.m optical window which also serves as a vertical current injection inlet give lasing threshold currents as low as 3.8 mA. The differential series resistance is (350-450) .OMEGA. with a diode voltage of (5.1-5.6) V at the lasing threshold. Far field pattern of the laser emission is Gaussian-like with a full width at half maximum of 7.degree..

Abstract: A process for the preparation of superconducting ceramic materials by a solid state reaction technique. The process is especially suited for production of powders including .gtoreq.95% of Ba.sub.2 YCu.sub.3 O.sub.7 for use in producing sintered ceramic bodies including >99% Ba.sub.2 YCu.sub.3 O.sub.7.

Abstract: A process is described for producing optical integrated circuits on lithium niobate substrates in which the composition of the lithium niobate substrates is adjusted by a powder bed equilibration procedure. This procedure involved exposure of the lithium niobate crystals to a powder bed in a crucible during a heat treatment. A similar procedure is used during production of optical integrated circuits to maintain the desired Li/Nb composition in the substrate.

Abstract: Devices are described which incorporate dielectric material with unusually low (and sometimes negative) temperature coefficient of dielectric constant. Such materials make possible the fabrication of microwave devices which remain stable with changing temperature. This is particularly useful for stabilization of frequency in microwave sources. Stabilization results from the incorporation of small amounts of tin in ceramic material containing mostly Ba.sub.2 Ti.sub.9 O.sub.20.

Abstract: A process is described for the preparation of ceramic dielectrics for microwave applications which yield high quality (Q) factors, high dielectric stability and excellent mechanical stability. The procedure is particularly useful where the size of the ceramic dielectric structures is large (average diameter greater than one inch).

Abstract: A ceramic composition and processing procedure is described which is useful in electric and electronic devices such as thermistors. The ceramic composition, which may be described as a semiconducting barium titanate, exhibits a large positive temperature coefficient of resistance. Advantages are ease and convenience of fabrication with lower sintering temperature than conventional processing and use of an air atmosphere instead of nitrogen or oxygen atmospheres. This facilitates batch processing and permits convenient sintering in a continuous kiln.