Improved Demagnetization Cryostat for Mossbauer Effect Experiments

概要

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Some improvements in a previously constructed demagnetization cryostat for use in Mossbauer effect experiments have been made. In the new design, a mechanical heat switch previously used for establishing thermal contact between the paramagnetic salt and the liquid helium bath was replaced with helium exchange gas; the use of vacuum-tight beryllium windows has made it possible. CrK alum or MnNH_4 Tutton salt weighing 60 g was used as a cooling salt. The lowest temperature reached by using CrK alum was 0.025°K and temperature of the alum arrived at 0.05°K in 6.5 hr. The lowest temperature reached by using MnNH_4 Tutton salt was 0.15°K and temperature of it was practically constant as long as liquid helium stayed in the bath. The magnetic hyperfine structure of K_3Fe(CN)_6 (T_N=0.13°K) has been observed by employing this cryostat, and the internal magnetic field at the position of an iron nucleus in K_3Fe(CN)_6 was found to be 193 kOe.
社団法人応用物理学会の論文
1968-02-05