Effect of Co substitution on the magnetic properties in Fe1−x Co x Ga3

Abstract

We investigated the effect of Co substitution in Fe_1−x Co _x Ga₃ by means of electric resistivity and magnetic measurements. Nearly ferromagnetic behaviors were observed in Fe_1−x Co _x Ga₃ system by the chemical substitution of Co for Fe in diamagnetic mother compound FeGa₃, accompanying with a semiconducting to metallic transition. With the substitution of Co, the magnetization of Fe_1−x Co _x Ga₃ increases first, and then decreases and finally it becomes diamagnetic. The magnetic properties of Fe_1−x Co _x Ga₃ were analyzed in terms of self-consistent renormalization (SCR) theory and Takahashi’s theory. The spin-fluctuation parameters, fourth order expansion coefficients of magnetic free energy (\({\bar{F}}_{1}\)), the magnetic susceptibility in the ground state X(0), the spectral widths of the spin fluctuation spectrum T ₀ and T_a in the frequency and wave-number spaces, respectively, were estimated from the parameters derived from magnetic measurements. The magnetic properties of Fe_1−x Co _x Ga₃ can be understood almost quantitatively by the SCR theory and Takahashi’s theory of spin fluctuations.