  We demonstrate that there is a strong diamagnetic response of metamaterials,
consisting of open or closed split ring resonators (SRRs). Detailed numerical
work shows that for densely packed SRRs the magnetic permeability,
$\mu(\omega)$, does not approach unity, as expected for frequencies lower and
higher than the resonance frequency, $\omega_0$. Below $\omega_0$,
$\mu(\omega)$ gives values ranging from 0.9 to 0.6 depending of the width of
the metallic ring, while above $\omega_0$, $\mu(\omega)$ is close to 0.5.
Closed rings have $\mu\approx 0.5$ over a wide frequency range independently of
the width of the ring. A simple model that uses the inner and outer current
loop of the SRRs can easily explain theoretically this strong diamagnetic
response, which can be used in magnetic levitation.
