Dependences of High Magnetic Permeability on Crystal Magnetic Anisotropy and Magnetostriction for “Nimalloy” in the Ni–Mn–Fe System

Abstract

Disk-shaped single crystal specimens with a (001) plane and rod-shaped polycrystal specimens were prepared from Ni–Mn–Fe alloys containing less than about 29% manganese and less than about 25% iron. Measurements of the crystal magnetic anisotropy K1 and the saturation magnetostriction λs were carried out for the specimens which were cooled from 650°C at a rate 26°C/sec after high-temperature heating. The absolute value of K1 increased with increasing iron concentration and then decreased steadily after passing through a maximum. The absolute value of λs decreased rapidly with increasing manganese and iron concentrations, reached zero value at nickel concentrations a little higher than Ni3(Mn, Fe), and then increased gradually. In a Ni–Mn–Fe alloy of about 20% manganese and about 5% iron that exhibits the highest permeability, the values of K1 and λs are fairly small. As is the case with Ni–Mn alloys, it is considered that the high permeability of the alloy comes from the very small values of K1 and λs.