HALL EFFECT AND RESISTIVITY MEASUREMENTS IN CoFe-BASED AMORPHOUS MAGNETIC ALLOYS

In this paper, a design and automation of a DC and AC Hall effect measurement system using a four-wire method is presented. This system consists of a Current Source (Model 6221 DC-AC, Keithley Instruments Inc.) connected to a Nanovoltmeter (Model 2182A, Keithley Instruments Inc.), and an electromagnet (Phylatex) that provides magnetic fields up to 0.8 T. This system has several measurement capabilities including Hall voltage, Hall coefficient, resistance, resistivity, and I-V curves, and can be operated in both DC and AC (up to 10 Hz) current modes (IAC, IDC). The functioning of the Hall effect measurement system was verified using both a standard sample of copper and several resistor circuits that correspond to simulated metallic and semiconductor samples. This measurement system was used to study the magneto-transport properties at room temperature of the soft magnetic amorphous ribbons Co64Fe21B15 and Co71Fe4B15Si10. An analysis of these magneto-transport properties is presented, too