Broadband left-handed materials made of thin soft ferromagnetic films with in-plane uniaxial anisotropy

We study theoretically characteristics of normally incident E-polarized microwave propagation in soft ferromagnetic films with in-plane uniaxial anisotropy, and find that due to the existence of the gyrotropic permeability tensor, the soft ferromagnetic film may become a left-handed material over a broad frequency band. Furthermore, the bandwidth and the frequency positions can be easily modified by the external magnetic field. Finally, the energy loss of the microwave propagating in the film is investigated.