We have developed a database for high magnetic field science and technology. Tsukuba Magnet Laboratory (TML) of the National Research Institute for Metals (NRIM) holds one of the world's leading high magnetic field facilities, incorporating external scientists from around the globe. We have established cooperative relationships with other high magnetic field laboratories worldwide. The NRIM is also a central organization of VAMAS activities for the standardization of measurement methods for superconductive materials. The database contains experimental results obtained at our facilities, standard references given by VAMAS and technological information provided by high magnetic field laboratories. However, from the user's point of view the database should be global, preferably including other fields of superconductivity and cryogenics. We will embody up-to-date results reported in symposiums, conferences and journals, and bring together existing data scattered throughout different sources into our database. We call it the “Engineering Database for Applied Superconductivity and Cryogenics”. Our system also includes “Reference Database” dealing with data sources, and “Technical Terms Database” as a thesaurus of the technical terms used in the field of superconductivity and cryogenics. The database can be accessed from around the world through the Internet using a web browser. This project will be conducted in cooperation with the Cryogenic Association of Japan. We would appreciate researchers' contributions to the engineering database.
We have measured the low temperature specific heats for Er (Ag1-xMx) (M=Al, Pd and Fe, x≤0.2) alloys over the temperature range of 1.5-25K to explore efficient regenerator materials suitable at low temperatures around 10K. In particular, the peak height of the volumetric specific heat of Er (Ag0.9Al0.1) alloy has reached 1.2J/(Kcm3) at 16.5K, which is 1.5 times higher than that of the ErAg compound previously reported. Its large specific heat is attributed to the 4-fold degeneracy in the ground state of the Er 4f-levels. Moreover, we have revealed that the addition of third elements M=Pd and Fe to the ErAg compound could lower the peak position of the specific heat to about 10K. We conclude that a series of the ternary Er (Ag1-xMx) (M=Al, Pd and Fe, x≤0.2) alloys can serve as good regenerator materials in the temperature range below 17K.
The mechanical properties of an (Nb, Ti)3Sn superconductor have been improved by using Ta as a reinforcer. The conductor was manufactured on an applicable continuous-piece length and showed 0.2% yield strength of 305MPa at 4.2K. Stress-strain characteristics could be explained by the mixture law with Ta itself and another part of the conductor. The dependence of critical current densities on plastic strain was studied based on the scaling law. The actual performances of the developed conductor exceeded all target values in the preliminary design of a 1GHz NMR magnet.