Determination of the magnetic phase diagram in the H-T plane for a sigma-phase Fe47Mo53 alloy: Double re-entrant transition

Abstract Magnetization measurements were carried out in the in field-cooled (FC) and in zero-field-cooled (ZFC) conditions versus temperature, T, and external magnetic field, H, on a sigma-phase Fe 47 Mo 53 compound. Analysis of the measured M FC and M ZFC curves yielded values of characteristic temperatures: magnetic ordering (Curie) temperature, T C , irreversibility temperature, T ir , temperature of the maximum in M ZFC , T m , identified as the Nėel (T N ) temperature, and cross-over temperature, T co . Based on these temperatures a magnetic phase diagram in the H-T plane was outlined. The field dependences of the characteristic temperatures viz. of the irreversibility and of the cross-over temperatures were described in terms of a power law with the exponent 0.5(1). In the whole range of H i.e. up to 800 Oe, except the one H ≤ 50 Oe, a rare double re-entrant transition viz. PM→FM→AF→SG takes place. For small fields i.e. H ≤ 50 Oe a single re-entrant transition viz. PM →FM→SG is revealed.