ELECTRIC AND MAGNETIC CHARACTERISTICS OF A CO-FE-SI-B-BASED AMORPHOUSWIRE AND ITS APPLICATION TO A MULTIVIBRATOR-TYPE MAGNETOMETER AT LOW-TEMPERATURE

Electric and magnetic characteristics of a Co-Fe-Si-B-based amorphous thin wire with a diameter of 120 mum were investigated at low temperat ures from an applicative point of view. The electric resistivity decre ases with the decrease of temperature and has the minimum point at abo ut 30 K. The maximum decrease of the resistivity is, however, only 2.7 % as compared with that at room temperature. The magnetic characterist ics in term of the coercive force, the saturation induction, and the m aximum permeability are all increased with the decrease of temperature . The coercive force shows the increase of 25% at 4.4 K as compared wi th that at room temperature; and the saturation induction and the maxi mum permeability about 15%. The very slight decrease of electric resis tivity and the increase of the coercive force with the decrease of tem perature promise a high-frequency application of the wire at low tempe rature. These results led to the fabrication of a multivibrator-type m agnetometer being able to work at low temperature below 77 K. The magn etometer has a sensitivity of about 1 mV/mG at room temperature in a m agnetic field range between +1 and -1 Oe. The sensitivity change is le ss than 0.5% even at low temperature of 6 K, as compared with that at room temperature.