Evidence for superparamagnetism in the niger meteorite

The Niger (I) carbonaceous chondrite has been investigated by Moessbauer Spectroscopy through the temperature range 4.2K <= T <= 300K and in applied magnetic field 5 KOe <= H{sub o} <= 60 KOe. The results showed that this meteorite contains an Fe{sup 3+} compound which exhibits superparamagnetic behavior below 80K. (author).