CONSTRUCTION AND VALIDITY OF LOW-COST-HIGHTEMPERATURE ac SUSCEPTOMETER

The design and construction of a simple, low cost, ac susceptometer operating in the temperature range of 30-400 0C (300-670 K) is being presented here. The measurements are made in terms of the change in mutual inductance by inserting a specimen inside one of the two secondary coils. Starting from basic formulae, a direct relationship between voltage and magnetic susceptibility to calculate the absolute susceptibility of magnetic materials has been developed. The validity of the apparatus is checked and verified with the help of the magnetic phase transitions temperatures of Ni and NiO as reference materials. Differential Scanning Calorimeter (DSC) has been used to counter check the magnetic phase transition temperatures of these reference materials. Purity of these materials has been checked using X-ray Diffractometry (XRD) analysis. The transition temperatures of both materials were found within ±3 0C in agreement with the transitions temperatures referred to in the literature. The strength of the constructed ac susceptometer is thus validated.