We propose a metamaterial with a three-layer structure based on Faraday’s law. The metamaterial is simply formed by a pair of homogeneous parallel plates separated by a thin medium. We also propose a virtual current loop with length of $2a$ ($a$ is the attenuation constant) in the plates, which can be formed upon excitation of an electromagnetic field. Strong magnetic response has been observed by spectroscopic ellipsometry and the resonant frequency can be widely tuned by varying the structure dimensions. The observations are also verified by optical transfer matrix. The easy fabrication and high interfacial quality of the structure will make the applications of the magnetic response and negative refractive index metamaterials a reality.

• Received 2 October 2006

DOI:https://doi.org/10.1103/PhysRevB.74.193105