  We demonstrate a thermally tunable optical metamaterial with negative
permeability working in the visible range. By covering coupled metallic
nanostrips with aligned nematic liquid crystals (NLCs), the magnetic response
wavelength of the metamaterial is effectively tuned through control of the
ambient temperature, changing the refractive index of LC via phase transitions.
By increasing the ambient temperature from 20 degree to 50 degree, the magnetic
response wavelength shifts from 650nm to 632nm. Numerical simulations confirm
our tests and match the experimental observations well.
