Transitions between spin-glass and ferromagnetic (or related) states in disordered Ni-Mn alloys

Abstract

Magnetic measurements reveal that the alloy Ni 78Mn 22 undergoes a field-induced spin-glass-to-ferromagnetic transition at a critical field that decreases from ≈ 140 Oe to zero as the temperature is raised from 4.2 to 40 K, its ferromagnetic Curie point being ≈ 270 K. The alloy Ni 74Mn 26 is found to have a related state of infinite initial susceptibility but no spontaneous magnetization between ≈ 80 and ≈ 155 K. Below 40 and 80 K, respectively, Ni 78Mn 22 and Ni 78Mn 22 exhibit the thermoremanent properties of a spin glass.