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Jones, C. K.

Publications and source records attributed to Jones, C. K..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Investigation of superconducting interactions and amorphous semiconductors

Research papers on superconducting interactions and properties and on amorphous materials are presented. The search for new superconductors with improved properties was largely concentrated on the study of properties of thin films. An experimental investigation of interaction mechanisms revealed no new superconductivity mechanism. The properties of high transition temperature, type 2 materials prepared in thin film form were studied. A pulsed field solenoid capable of providing fields in excess of 300 k0e was developed. Preliminary X-ray measurements were made of V3Si to determine the behavior of cell constant deformation versus pressure up to 98 kilobars. The electrical properties of amorphous semiconducting materials and bulk and thin film devices, and of amorphous magnetic materials were investigated for developing radiation hard, inexpensive switches and memory elements.

Janocko, M. A.↗
NASA NTRS1972

Magnets with stabilized conductors

Method fabricates stabilized composite conductor, for use in construction of magnets, using equal amounts of superconducting and metal materials, thus reducing weight, cost and size.

Jones, C. K.↗
NASA NTRS1972

Superconducting properties of annealed Nb-Al-Ge thin films.

Discussion of the superconducting transition temperature and other superconducting properties of annealed Nb-Al-Ge thin films which were prepared by sputtering from a 3Nb-0.8Al-0.2Ge cathode. Annealing was performed in a high-vacuum environment maintained at 10 to the minus 9th torr or less, for times and temperatures near the optimum conditions for bulk Nb-Al-Ge. Films with transition temperatures from 12 to 16 K were annealed and in all cases a rise in transition temperature was observed, with the maximum value obtained thus far being 17.5 K. The current carrying capacity values, already substantially higher for unannealed thin films than for the bulk, were raised even further in the annealed samples, indicating that annealing has no detrimental effects on the flux pinning in these films.

Janocko, M. A.↗
NASA NTRS1972

Superconductivity in thin films of the Mo-Re system.

A series of Mo-Re alloy films has been prepared by sputtering from a composite molybdenum and rhenium cathode. These films were deposited in an ultra-high purity environment onto sapphire substrates which were held at temperatures ranging from 400 to 1300 C. Maximum transition temperatures observed were 15 K which is significantly greater than the highest reported bulk values. Critical current and field characteristics also were found to be considerably greater in the films compared to corresponding bulk samples. Upper critical fields of over 100 kOe were measured. These enhanced properties are discussed in relation to the structural characteristics of the sputtered films.

Gavaler, J. R.↗
NASA NTRS1971

Alternating current losses of stabilized NbN.

The ac losses of thin films of NbN have been measured on uncoated samples and samples coated with copper and aluminum. The reversibility of the superconducting to normal transition was studied under conditions of swept current at fixed field and swept field at fixed current. Results show that thin films of NbN can be stabilized by using normal metal overlays, and that ac losses in the stabilized material are substantially lower than those in the equivalent unstabilized material.

Deis, D. W.↗
NASA NTRS1971

Superconducting properties as a function of thickness in NbN films.

Measurement of the superconducting properties of NbN films prepared by a high purity reactive sputtering process. The transition temperature was found to decrease with decreasing film thickness, while in contrast the critical current vs magnetic field was largely independent of film thickness and even slightly increased when the film thickness went down to 100 A. The average resistivity of the NbN films was 1000 microohm-cm.

Gavaler, J. R.↗
NASA NTRS1971

Ultrasonic attenuation in superconducting molybdenum-rhenium alloys.

Investigation of longitudinal sound attenuation in superconducting Mo-Re alloys as a function of temperature, magnetic field, and frequency. Evaporated thin film CdS transducers were used for the measurements at frequencies up to 3 GHz. The normal state attenuation coefficient was found to be proportional to the square of frequency over this frequency range. Measurements in zero magnetic field yielded a value of the energy gap parameter close to the threshold value of 3.56 kTc, appropriate to a weakly coupled dirty limit superconductor.

Ashkin, M.↗
NASA NTRS1971

Characteristics of NbN Dayem bridges

NbN Dayem bridge characteristics, discussing negative resistance region, self induced subharmonic current steps, temperature dependence and microwave radiation effects

Blaugher, R. D.↗