And we test how the laser ' s intensity changes with time through six kinds of cofe2o4 ionic magnetic fluid when laser has the same direction as the magnetic field ( be perpendicular to the magnetic fluid film ) 用相消法设计了测试磁光效应一一透射光强的装置,测试了光线与外磁场方向一致(都垂直于磁性液体薄膜)的情况下,透过六种cofe 。 0 。