MAGNETIC-RELAXATION IN SM2FE14GA3 AND SM2FE14GA3C

Magnetic after-effect measurements of Sm2Fe14Ga3 and the carbide Sm2Fe 14Ga3C were performed in the temperature range of 140 to 450 K. In the case of Sm2Fe14Ga3C, the relaxation spectrum is composed of two chara cteristic maxima at 220 and 320 K. The latter maximum is not present i n Sm2Fe14Ga3 and therefore assigned to local jumps of interstitially d issolved carbon atoms while the former is attributed to hydrogen. Nume rical evaluation yielded an activation enthalpy of (0.96 +/- 0.02) eV and a pre-exponential factor tau(0) = 3 x 10(-14+/-0.5) s for the shor t-range diffusion of C atoms. The corresponding values for the short-r ange diffusion of hydrogen are (0.64 +/- 0.04) eV and tau(0) = 3 x 10( -14+/-1) s. (C) 1998 American Institute of Physics. [S0021-8979(98)016 11-9].