Influence of Joule heating on electrical resistivity in Co-rich amorphous microwires

摘要

The paper investigates the electrical resistivity of two types of the glass-coated Co-rich amorphous ferromagnetic microwires during the Joule heating by direct current. We measured the relationships between the microwire's resistivity and the power, which applied to the samples in as-prepared and crystallized conditions. Both types of microwires were demonstrated to completely crystallize on exposure to a temperature of more than 600 °C. During heating by a power up to 2.5 W (～400 °C), the microwires with Mo-Ni content were characterized by a monotonic resistivity increase with the temperature. But the microwires with Cr content had a well-marked resistivity minimum near the temperature T_M ～ 163 °C. This minimum shifted to a temperature value of ～260 °C after annealing. The research shows that the temperature dependence of resistivity in the temperature range below T_M obeys the f(T) = -ln(T) law.