Application of polarized recoil-free γ rays

Polarized (circularly and linearly) recoil-free γ rays have been utilized in recent years in various experiments. Of particular interest are investigations with linearly polarized γ rays. Various methods of producing linearly polarized recoil-free γ rays will be discussed. Examples will be presented where the spin orientation in a magnetic material and the principal axis of the electric field gradient were obtained by rotating a crystal to the position giving maximum or minimum resonance absorption. In a Mössbauer polarimeter the dispersion associated with the resonance absorption is of interest. The Mössbauer-Faraday effect and Mössbauer magnetic double refraction have been observed.