The magnetic susceptibility of antiferromagneytic and ferrimagnetic compounds

Abstract

A simple cryostat is constructed for the measurement of magnetic susceptibility in the temperature range 77 to 300 K. The tunnel diode oscillator and the amplifier have been built as the resonant circuit for measuring the change of the frequency corresponding to the susceptibility of the sample. The temperature was measured by means of the thermal e.m.f. of the chromel-alumel thermocouple. Ferrite, ferrous oxalate and cupric acetate monohydrate were used to check the frequency fluctuation. The magnetic susceptibility of Cu(CH₃COO)₂ . H₂O between low temperature to room temperature have been studied. The maximum in the susceptibility was observed at temperature Tm = 250±5K and the Curie temperature is found to be 198±5K. The Curie constant of this sample also to calibrate the geometric filling factor, F, of the apparatus. The second filling factor, f, which is due to the density of the sample is obtained. This apparatus can be used to measure the magnetic properties of other compunds.