Barnes S E, Maekawa S
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Phys Rev Lett. 2007 Jun 15;98(24):246601. doi: 10.1103/PhysRevLett.98.246601.
The usual Faraday's Law E=-dPhi/dt determines an electromotive force E which accounts only for forces resulting from the charge of electrons. In ferromagnetic materials, in general, there exist nonconservative spin forces which also contribute to E. These might be included in Faraday's Law if the magnetic flux Phi is replaced by [Planck's constant/(-e)]gamma, where gamma is a Berry phase suitably averaged over the electron spin direction. These contributions to E represent the requirements of energy conservation in itinerant ferromagnets with time dependent order parameters.
通常的法拉第定律(E = -d\Phi/dt)确定了一个仅由电子电荷产生的力所导致的电动势(E)。一般来说，在铁磁材料中存在非保守自旋力，它们也对(E)有贡献。如果磁通量(\Phi)被([普朗克常数/(-e)]\gamma)取代，其中(\gamma)是一个在电子自旋方向上适当平均的贝里相位，那么这些力可能会被包含在法拉第定律中。对(E)的这些贡献代表了具有随时间变化的序参量的巡游铁磁体中能量守恒的要求。
