Electron scattering mechanisms in amorphous ferromagneticFe80B20

The temperature dependence of the resistivity of many amorphous metals, including ferromagnetic ones, has been fitted reasonably well to integral power laws ($T^2$ at intermediate temperatures and $T$ at higher temperatures), in agreement with predictions of the extended Ziman theory including electron-ion potential scattering only. The dominant temperature dependence corresponding to electron-magnon scattering is $T^{1.5}$, and recent results on some amorphous ferromagnets show satisfactory fits to such a power law. However, it may not be easy to distinguish between exponents differing by only 0.5, so that nonsubjective methods of data analysis should be used. Seven samples of amorphous ${\mathrm{Fe}}_{80}$ ${\mathrm{B}}_{20}$ from two separate melt-quenching runs were used in this study. A small but measurable difference in the temperature dependence of resistivity was found for the different runs. A nonlinear-least-squares—finite-difference technique was used to fit the resistivity data to power laws. In the temperature interval $20\lesssim T\lesssim 100$ K, the best half-integral power-law exponent is 1.5. This exponent and its coefficient are consistent with predictions of the effect of the electron-magnon scattering mechanism; however, arguments are presented which weaken the case for the significance of this consistency.