A simple method for the measurement of the temperature variation of initial magnetic susceptibility between 77 and 1000 K

Abstract

Two identical multi-layered solenoids each enclosing a water jacket are used in an a.c. bridge circuit so that inclusion of a sample in either coil produces an out of balance signal proportional to the susceptibility of the sample. This signal is then amplified with low noise field effect transistors, converted to direct current with a phase sensitive detector, and displayed against temperature on an XY recorder. The water jacket of one solenoid contains a furnace capable of reaching 700°C, while the other contains a cooling assembly for use between liquid nitrogen and room temperature. The temperature variation of susceptibility allows determination of Curie and transition temperatures.