Effect of Co substitution on the magnetic properties in Fe1−xCoxGa3

Abstract

We investigated the effect of Co substitution in Fe1−xCoxGa3 by means of electric resistivity and magnetic measurements. Nearly ferromagnetic behaviors were observed in Fe1−xCoxGa3 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 Fe1−xCoxGa3 increases first, and then decreases and finally it becomes diamagnetic. The magnetic properties of Fe1−xCoxGa3 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 (), the magnetic susceptibility in the ground state X(0), the spectral widths of the spin fluctuation spectrum T0 and Ta in the frequency and wave-number spaces, respectively, were estimated from the parameters derived from magnetic measurements. The magnetic properties of Fe1−xCoxGa3 can be understood almost quantitatively by the SCR theory and Takahashi’s theory of spin fluctuations.