低温熱処理によるミュメタルの磁化温度曲線の変化について

抄録

The magnetic properties of an iron-nickel alloy (Mu-metal), that is, H_c(coercive force), μ₀(initial permeability) and μ_m(maximum permeability）were found remarkably changed by additive heat treatment at the temperature range from 300° to 600°C. At the same time, the change of electrical conductivity and the anomalous curve of specific heat were induced by this heat treatment. In general, the magnetic induction falls with rising temperature. But, when the magnetic field strength was less than 0.1 Oe, the thermal demagnetization curve near the Curie temperature was varied with the low temperature heat treatment. Under high field strength (H=2.5 Oe and more), however, this phenomenon was not observed. On the Mu-metal annealed at temperature range from 500° to 550°C, the thermal demagnetization curve considerably shifts to the side of lower temperature, as compared with that of a sample annealed at temperature lower than 480°C or not subjected to heat treatment.