A basic research program is proposed to study capacitive energy storage at 77 k based on cadmium-lead niobate ceramics for two reasons: (1) the dielectric constant is unusually large at these temperatures (\8000); and (2) the ferroelectric transition can be compositionally adjusted below 77 k. two… More

This program is based on the discovery of varistor characteristics at 4.2 degrees k in a new zno ceramic composition, and rough estimates suggest that a small (-0.1 cm) cryovaristor device based on this material would switch at -4 v and carry -10 ka. it is planned to measure the electrical and… More

The signal-to-noise ratio of infrared detectors increases dramaticallyas the temperature of the detector is reduced to cryogenic temperatures and there has been a substantial improvement in cryocoolers to meet this need. however, valves of one type of cryocooler, the joule-thompson expansion… More

An enormous magnetocaloric effect has been discovered in fine-grain spinel powders at liquid helium temperatures. for example, an adiabatic-demagnetization temperature drop from 8.5 to 5.0 k has been measured with a magnetic field ofonly 3.8 gauss; these effects have been duplicated on four powder… More

The high-tc superconductor bicasrcu-oxide and the ferroelectric bi4ti3o12 have a-, b-, and c-lattice constants that match almost exactly. single crystals of thebi-ferroelectric are available in the form of large thin plates where the c-axis is perpendicular to the plate, and thin/thick films of the… More

This project will measure for the first time the dielectric properties of seven categories of ceramic materials at 2 k to develop capacitor components for detectors and detector arrays. all ceramic samples are in the form of multilayer capacitors or can be made in this form by conventional ceramic… More

A ph i research program is proposed to develop baseline thermal data for dielectric materials in the range 20 to 77k for thermal-management applications with the new high temperature ceramic superconductors. these ceramic superconductors are being considered for a 1 mw air force generator. candidate… More

Japanese researchers have recently developed er-based alloys that have large specific heats below 15k, and have demonstrated improved regenerator performance using these materials. these alloys, however, are very expensive and brittle. this project focuses on inexpensive ceramics that have much… More

A six-month, $91,305 Phase I SBIR program is proposed to perform ceramic-composition R&D aimed at cryogenic capacitors for the 120 - 240 K temperature range. Candidate compositions from three families of ceramics will be made under subcontract by NexTech Mat'ls Ltd and measured by CeramPhysics, 120… More

An assessment will be made of two quench-protection strategies for HTS conductors, one based on dielectric insulations with enhanced thermal properties and the other on a cryovaristor technology. Three insulations are considered: ceramic powders in Formvar, sputtered ceramics, and diamond films. … More

The quench-protection strategy at 77 K identified in the Phase I STTR program involves depositing a thin film of a ceramic insulation having a large thermal conductivity at 77 K. Two ceramics were identified for this strategy, ZnO and Zn2GeO4, and in the Phase II STTR program the deposition… More