Anomalous behaviour of the Debye temperature in Fe-rich Fe-Cr alloys

Debye temperature, Theta(D), of Fe-rich Fe100-xCrx, disordered alloys with 0 <= x <= 30 was determined from the temperature dependence of the centre shift of Mossbauer spectra recorded in the temperature range of 60-300 K. Its compositional dependence shows a non-monotonous behaviour with two maxima: a sharp maximum at x approximate to 3 having a relative increase of similar to 12% compared to a pure iron, and a broad one centred at x approximate to 15 with a relative height of similar to 10%. The maxima coincide well with those found or calculated for various physical properties like the spin-waves stiffness coefficient, D-o, the magnetic moment per Fe atom and the Curie temperature, suggesting a magnetic origin as a possible source of the anomalous behaviour of Theta(D) observed in this study. (C) 2009 Elsevier B.V. All rights reserved.