# Refractive index for magnetic material

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1. Nov 18, 2015

### wasi-uz-zaman

hi, I have studied the general expression for metamaterial as

n=√(εμ)
for dielectric relative permeability is one and we have
n=√ε,
but what would be the refractive index for magnetic material , by seeing symmetry I figure out as
n=√μ
will it be valid and we have Lorentz model for dielectric do we have some model for magnetic material.
thanks
wasi

2. Nov 18, 2015

### DrDu

This is possible but not very general. Magnetic effects are but a special case of spatial dispersion. It is better to set $\mu=1$ and describe all possible magnetic effects in terms of a dielectric function depending not only on frequency but also on wavenumber, i.e. $n=\sqrt{\epsilon(\omega,\mathbf{k})}$.

3. Nov 18, 2015

### wasi-uz-zaman

thanks but for magnetic material
n=√μ

is this a valid expression for refractive index of magnetic materials.

4. Nov 18, 2015

### DrDu

Yes, of course

5. Nov 19, 2015

### wasi-uz-zaman

thanks a lot

Last edited by a moderator: Nov 19, 2015