Spontaneous strain glass to martensite transition in ferromagnetic Ni-Co-Mn-Ga strain glass

We report that a spontaneous strain glass to martensite (STG-M) transition occurs in a Ni₄₅Co₁₀Mn₂₀Ga₂₅ ferromagnetic strain glass. The signatures of the spontaneous STG-M transition of Ni₄₅Co₁₀Mn₂₀Ga₂₅ ferromagnetic strain glass are stronger than those of Ti₅₀Ni_44.5Fe _5.5 strain glass reported previously. Such a difference is attributed to that the martensitic terminal of the former has larger elastic anisotropy than that of the later. The spontaneous STG-M transition in this ferromagnetic strain glass is due to that the delicate competition between the kinetic limitation and the martensitic thermodynamic driving force changes with temperature.