Paramagnetism: The Curie Law

Abstract

This is a book concerning the magnetic properties of transition metal complexes. The subject has been of interest for a long time, for it was realized as long ago as the 1930’s (1) that there was a diagnostic criterion between magnetic properties and the nature of the metal ion in a complex. Indeed, over the years, magnetic properties have continued to be used in this fashion. With time, the emphasis has changed, so that now chemists are becoming more interested in the magnetic phenomena themselves, and the subject is no longer a subsidiary one. One result of this new emphasis, which is hopefully rationalized and explained by this book, is that chemists must continue to decrease the working temperature of their experiments, with measurements at liquid helium temperatures now becoming common. In other words, the careful study of magnetic properties of transition metal complexes at low temperatures is essentially a redundant statement. Thus, little mention will be made of the many experimental results that pertain to high temperatures, that is, the temperatures of liquid nitrogen and above. The reason for this is simple, that the quantities which are being sought, such as the ground state energy levels, make a far more significant contribution to the measured phenomena at low temperatures. The emphasis is on measurements carried out on single crystals.