Magnetic Properties of the Monosilicides of Some 3d Transition Elements

Abstract

Motivated by the recent observation¹ of the unusual electronic properties of FeSi, as manifested in the ⁵⁷Fe Mössbauer effect and ²⁹Si NMR, the magnetic susceptibilities of the monosilicides of Cr, Mn, Fe, Co, and Ni were determined as a function of temperature from 1.4° to 300°K in fields up to 15 kOe. The silicides of Cr, Mn, Fe, and Co have the cubic B‐20 structure and NiSi has the orthorhombic B‐31 structure. NiSi and CoSi are diamagnetic and show essentially a temperature‐independent susceptibility. CrSi exhibits temperature‐independent paramagnetism. FeSi is paramagnetic with an unusual temperature dependence of the susceptibility.¹ The susceptibility increases with increasing temperature with χg=0.77×10⁻⁶ at T=90°K and χg=8.3×10⁻⁶ at T=300°K. Although FeSi is paramagnetic and CoSi is diamagnetic some solid solutions of the two compounds are ferromagnetic at low temperatures. MnSi orders magnetically at 30°K. At 1.4°K the magnetization curve is linear up to a field of 6200 Oe where it saturates abruptly. The saturation moment per Mn atom at 1.4°K is 0.4 _μB, which is smaller than the value 1.4 _μB one obtains in the paramagnetic region. Dilute solutions of Ru, Rh, Cr, Mn, Fe, and Ni in CoSi become paramagnetic with Curie‐Weiss behavior.