Magnetic and Mössbauer Studies of Metamagnetic Fe₃Ga₄

Abstract

Magnetization of Fe₃Ga₄ is measured as a function of magnetic field and temperature. In weak fields, Fe₃Ga₄ is an antiferromagnetic with a Néel temperature of 392 K. In strong fields, it shows a metamagnetic transition and gives a saturation moment of 1.27 μ_B per Fe atom at 4.2 K and 70 kOe. Its Mössbauer spectrum is analyzed into four sextets, assigned to the crystal site Fe(1), Fe(2), Fe(3) and fe(4): each site has, respectively, an internal field of 225, 190, 150 and 171 kOe at 80 K. The magnetic phase diagram of Fe₃Ga₄ involving the metamagnetism can be explained by the Moriya-Usami theory.