Integrated circuit ac mutual inductance bridge for magnetic susceptibility measurements.
A versatile ac mutual inductance bridge is described which uses integrated circuit operational amplifiers (op-amps) for the measurement of magnetic susceptibilities of ferro-, ferri-, and para-magnetic samples. The circuit employs op-amps both for balancing the bridge and for detecting the differential signal from the sample coil. The response of the circuit is linear over a wide range of sample susceptibilities, and is calibrated directly in absolute units (emu) using a multiturn digital potentiometer. The sensitivity of the instrument for weak paramagnetic samples (1 g) is +/-3x10(-7) emu.
Brodbeck
C M
CM
Department of Physics, Loyola University of Chicago, Chicago, Illinois 60626.
Bukrey
R R
RR
Hoeksema
J T
JT