Understanding the physical properties of nanosized materials is crucial to the development of nanodevices. Magnetic properties are a case in point. Nanometer-sized materials differ greatly from macroscopic materials in their magnetic properties. Graphite, for example, is nonmagnetic in macroscopic form but becomes magnetic at nanometer sizes. Alkaline metal becomes magnetic as nanosized clusters in a confined space, such as nanotunnels in zeolite.

Toshiaki Enoki, Kazuyuki Takai, and their colleagues studied the magnetic properties of potassium clusters physisorbed in a nanoporous host of magnetic nanographite. Ca60 potassium atoms subjected to a slight electron transfer modified the magnetism of the p-electron spins of the host nanographite. The 4s electrons that remained in the potassium clusters became localized and formed antiferromagnetic clusters. This is a new kind of nanomagnet. Composed of nonmagnetic elements, it exhibits novel magnetism at room temperature.