Discovery of ferromagnetism in new multicomponent alloy Ti–Nb–Cr–Ru

Abstract

We report the discovery of ferromagnetism in the cubic CsCl-type Ti21∼25Nb20∼24Cr5∼10Ru∼49 multicomponent alloy. In metals, the appearance of ferromagnetism due to the Cr magnetic moment is a rare phenomenon. The purest sample shows ferromagnetism with the Curie temperature of 38 K. The effective magnetic moment and the Weiss temperature are 3.67 μ B/Cr and 58 K, respectively, derived from the temperature dependence of dc magnetization. These values mean the ferromagnetic exchange interaction between the localized Cr magnetic moments. The ferromagnetic nature is also confirmed by the isothermal magnetization curve with the highest magnetization of 1.1 μB/Cr at 2 K. The electronic structure calculation also supports a ferromagnetic ground state in the CsCl-type structure. We further investigated the effect of elemental substitution on the ferromagnetic behavior. The partial substitution of Pd for Ru heavily suppresses the Curie temperature, indicating that the Ru atom may play an essential role in sustaining ferromagnetism. Ti21∼25Nb20∼24Cr5∼10Ru∼49 would be the first example of the ferromagnetic Cr-containing multicomponent alloy, and this study shows the usefulness of the large compositional space in exploring novel phenomena.