VARIATION OF ELECTRICAL-RESISTIVITY ASSOC IATED WITH ISOCHRONAL ORDERING IN AN FECO ALLOY

The temperature derivative of electrical resistivity, alpha R, in an F eCo alloy was measured with a constant rate of increasing temperature, and the residual resistivity was also measured at the liquid-nitrogen temperature as a function of quenching temperature. We proposed a kin etic equation for alpha R, which includes the change of vacancy concen tration and the degree of order S with the annealing time, and then an alyzed the experimental results by using the equation. It was found th at the electrical resistivity and the residual resistivity decrease ap proximately in proportion to S-2. The electrical resistivity by magnet ic scattering, however, hardly decreases with increasing S. Further, a lpha R caused by only the ordering, or Delta alpha R, was estimated by eliminating other effects, namely the magnetic and phonon scattering effects in disordered alloys. The observed Delta alpha R was analyzed by our kinetic equation, and the behavior of Delta alpha R on isochron al ordering was interpreted satisfactorily.