Thermomagnetic Analysis — A Powerful Tool for Metal Physics

Abstract

The low-field a. c. and d. c. susceptibility has been used for many years to determine magnetic phase-transitions as a function of temperature. The temperatures of these phase-transitions from the magnetically ordered to the paramagnetic state are the Curie temperature, the Neel temperature, and the spinglass freezing temperature for ferromagnetic, antiferromagnetic or ferrimagnetic and spinglass materials, respectively. Furthermore, the superconducting transition temperature is characterised by a transition from para- to diamagnetism, and can therefore also be determined very precisely. The theoretical background of the low-field (10⁻⁵ Oe < H < 100 Oe) d. c. and a. c. susceptibility, the so-called initial a. c. or d. c. susceptibility χa is, however, not really clear for a polycrystalline material, because of the variety of important parameters influencing χa.

Presented at the 10th Kolloquium über metallkundliche Analyse, Wien, 3.–5. November 1980. — Dedicated to Prof. Dr. Hanns Malissa on the occasion of his 60th birthday.