ELECTRICAL-RESISTIVITY OF GLASSY (FEXNI100-X)80B20 (X=30, 40, 50, 60, 70) ALLOYS AT ELEVATED-TEMPERATURES

Electrical resistivity (ρ) of glassy (FexNi 100-x)80B20 (x=30, 40, 50, 60, 70) has been studied as a function of temperature (T) between 300 and 1000 K using heating rates of ∼2.5 K/min. The slopes of the ρ vs T curves are positive for all the alloys in their glassy state. At the crystallization temperature the quantity ρ abruptly decreases. This decrease increases rapidly with the Fe content. No anomalies in the ρ vs T curves are observed at the corresponding Curie temperatures. For the sample containing 40 at.%Fe, ρ ∼ T between 300 and 600 K. All other samples show considerable deviations from this relationship. The quantity dρ/dT at 400 K increases with increasing ρ at 400 K for alloys with x = 40, 50, 60, and 70. The crystallization temperatures determined from the ρ vs T plots are in good agreement with values obtained by other techniques. A few comments are made on the nature of crystallization processes in this system.