Critical exponents of (Fe,Mn)(3)Si

The magnetic phase transitions in Fe3-xMnxSi alloys are investigated by mea suring the magnetisation as a function of magnetic field and temperature. T he magnetisation measurements have been carried out on three samples with x = 1.15, 1.3 and 1.5. The ferromagnetic transition temperature (T-C) critic al amplitude and critical exponents (beta, gamma and delta) have been deter mined by using Arrot plots, Kouvel-Fisher methods and scaling plots of the reduced magnetisation and reduced magnetic field. The values of beta, gamma and delta are discussed and compared with the results of various theoretic al models. (C) 1999 Elsevier Science B.V. All rights reserved.