Ageing effects in nanocrystalline Co50Ni50 and Fe50Ni50 alloy: Role of magnetic anisotropy

► Contrast ageing effect in Co50Ni50, Fe50Ni50 of close particle size, volume fraction. ► Co50Ni50 reveals superparamagnetic-like, Fe50Ni50 shows superspin-glass-like feature. ► Much different magnetic anisotropies lead to the contrast magnetic properties.