| 摘要 |
PURPOSE:To remove an offset voltage without measuring it by finding a difference in Hall voltage obtained by inverting the direction of a magnetic field. CONSTITUTION:A CPU 21 controls a power source 25 to supply currents to electromagnets 26 and 27 and the magnetic field which increases by 750 gauss stepwise at step intervals of three seconds is applied to a sample 28. At this time, a specific current is supplied from a current source 23 to the sample 28. In a stable state where the magnetic field reaches 3,000 gauss, a voltage W1 induced at the sample 28 is measured by a voltmeter 22 and the measurement data is read in the CPU 21. Then the applied magnetic field is reduced by 750 gauss stepwise at step intervals of three seconds and inverted. Then a voltage W2 induced at the sample 28 is measured 22 in a stable state wherein the magnetic field of 3,000 gauss is applied, and the measurement data is read in the CPU 21. Then the CPU 21 computes V=(W1-W2)/2 and calculates the mean value of the net Hall voltage V.
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