Magnetostriction of magnetite in the vicinity of the low-temperature transition

The temperature dependence of the magnetostriction constants in a magnetite single crystal is measured with the aid of a three terminal capacitance method. The magnetostriction constants λ100 and λ111 in a cubic phase are −15.9 × 10−6 and 78.6 × 10−6, respectively, at room temperature, and they are −20 × 10−6 and 20 × 10−6, respectively, just above the transition temperature. Prior to the magnetostriction measurement from liquid nitrogen temperature to the transition temperature, a 14 kOe magnetic field is applied to the crystal during cooling through the transition in order to remove the effect of twin formation as far as possible. Mutually independent nine magnetostriction constants corresponding to the orthorhombic phase are obtained.