Effects of the Berry Phase in Magnetic Nanostructures

Spin-carrying particles (e.g., electrons) subject to a spacially non-uniform exchange (or Zeeman) field acquire a phase (know as the Berry phase) depending on the topology of the non-uniform exchange field. This effect is analogous to the Aharonov-Bohm phase acquired by a charged particle via its orbital motion in a magnetic vector potential. The Berry phase therefore leads to effects similar to those produced by a real magnetic field or vector potential. Such effects are currently the topic of intense research activeties in the field of magnetic nanostructures. In particular, I shall discuss the topological Hall effect due to the Berry phase, as well as spin-analogues of the Aharonov-Bohm interferences.