High field transitions in (FeMn)3Si alloys : 37th Annual conference on magnetism and magnetic materials

1089-7550

AIP Digital Archive

Physics

The magnetic ordering in the series of solid solutions Fe3−xMnxSi having the D03 structure has been extensively studied at low fields over a wide range of temperatures. The present study reports observations of high-field-induced transitions in the low temperature range below the reordering temperature TR for members of the series falling within the concentration range 1.6≤x≤1.8. These alloys appear antiferromagnetic in low fields below TR but application of a field within the range up to 12 T results in a transition to an apparently ferromagnetic state. The transition occurs at all temperatures below TR and occurs reversibly except at the lowest temperatures where the hysteresis may be ∼0.5 T. The variation of the critical field with temperature follows an approximately quadratic form. Above TR Arrott plots suggest for the alloy with x=1.70 that a narrow ferromagnetic regime exists over the range 65≤T≤85 K above which the material is paramagnetic. For the alloy with x=1.75 however the Arrott plots suggest a direct conversion to paramagnetism at the reordering temperature TR indicating a possible phase diagram similar to that of Au2Mn. A discussion is given in terms of a model previously proposed to explain the low-field behavior.

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