Polarization and thickness effects in Mössbauer spectroscopy

Abstract

The relative line intensities of a magnetic hyperfine spectrum reflect the polarization of emitting and absorbing γ-rays. In resonatly thin absorbers spin orientation can be derived. In very thick samples each polarized line (circular or linear) can absorb by itself only up to one half of the resonant γ-rays from an unpolarized source. For the other half, with opposite helicity or linearity, the material is transparent (dichroism). Two effects in α-Fe will be described:

• 1. When two lines of opposite polarity are in close proximity an apparent line may developin between the actual resonance lines.

• 2. A thick absorber in a transverse magnetic field may exhibit small-but sharp-lines on top of the broad resonance lines.