Define the new material as Normal. Then on the material parameters window go on dispersion and thick user on magnetic dispersion. At that stage a dispersion list button will appear. Clicking this button a new window will appear. Here you will have the opportunity to load your file.

As Dr. Zanini is saying absolutely correct. Either you can go with that or you can define new material with mue and epsilon value as well as loss tangent for that particular material. This way is simple and completely manual.

Thanks,

Thanks four your answers.

Thank you all, i just have question , there are lot of variables to set beside Mue and epsilon , what is their importance in material properties ?

hello i want ferrite  file as txt  

How I define silver nitrate as new material, what is the property needed