Moment-Induced Magnetic Scattering and Magnetovolume Effect in Fe₆₅(Ni_1−xMn_x)₃₅ Alloys

Abstract

The temperature dependences of electrical resistivity and thermal expansion were measured for face-centered cubic Fe₆₅(Ni_1−xMn_x)₃₅ ternary alloys. The electrical resistivity of ferromagnetic alloys (x<0.3) decreases with increasing magnetic ordering. In contrast to this, the resistivity of antiferromagnetic alloys (x>0.3) increases below the Néel temperature and shows a resistance minimum. These behaviors are explained in terms of the magnetic scattering by induced moments below the magnetic ordering temperature. The expansion of volume due to the magnetic ordering was observed in both ferro- and antiferromagnetic alloys. To explain the volume expansion by the magnetic ordering, a new mechanism of magnetovolume effect based on the change of cohesive energy due to the spin polarization in 3d band is proposed.