Giant magnetodielectric metamaterial
  Dielectric materials with tunable permittivity are highly desirable for wireless communication, radar technology. However, the tunability of dielectric properties in the microwave frequency range and higher is an immense challenge for conventional materials. Here, we demonstrate a giant magnetodielectric effect in the GHz region in a metamaterial based on ferrite unit cells. The effect is derived from the coupling of the ferromagnetic resonance and the Mie resonance in the ferrite unit cells. Both the simulated and experimental results indicate that the effective permittivity of the metamaterial can be tuned by modifying the applied magnetic field, and a giant magnetodielectric effect, [{\epsilon}'(H) - {\epsilon}'(0)]/{\epsilon}'(0) = 15000 % at 11.284 GHz, is obtained. This mechanism offers a promising means of constructing microwave dielectrics with large tunable ranges and considerable potential for tailoring via a metamaterial route. 
Ke Bi, Ji Zhou, Xiaoming Liu
cond-mat.mtrl-sci