Calorimetric ac-loss measurement of high Tc-tapes at 77 K, a new measuring technique

✍ Scribed by Curt Schmidt

• Book ID: 104112083
• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 217 KB
• Volume: 40
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/s0011-2275(00)00014-x

✦ Synopsis

A method is described for calorimetric ac-loss measurements of high T c -tapes at 77 K. It is based on a technique approved at 4.2 K for conventional superconducting wires which allows a very easy and precise loss measurement in parallel or perpendicular external ®eld orientation. The slight temperature increase of the sample in an ac-®eld, thermally insulated from the liquid nitrogen bath, is used as a measure of losses. The thermal insulation is provided by a material of low thermal conductivity, no vacuum vessel is used. Simultaneously the sample magnetization can be measured. All necessary sensors are incorporated in the sample holder allowing a rapid sample change. The combination of the calorimetric method at 77 K with the easier magnetization measurement allows to determine the ac-losses in a wide frequency and amplitude range of the external ac-®eld. The main part of data is obtained by the magnetization measurement while the calorimetric measurement is used for calibration.