Magnets, molecules and quantum mechanics

In 1990 one of us (LG) published an article in Physics World on quantum tunnelling in magnetic particles that are a few nanometres in diameter. The article emphasized both the fundamental challenges – for instance understanding the nature of the transition region between quantum and classical regimes – as well as the technological obstacles to controlling and exploiting quantum coherent tunnelling in nanoscopic devices. The subject of quantum tunnelling of magnetization (QTM) was in its infancy. Since then, however, many experimentalists and theorists have contributed to this rich field. In 1994, for instance, the first workshop on the subject was held in Chichilianne, France (see Gunther and Barbara in further reading), and interest in quantum phenomena in magnetic molecules continues to grow.