Hyperfine Fields at Sn119 Nuclei in Ordered Fe‐Co and γ‐Fe‐Mn

Mossbauer results for the temperature dependence of Sn119 hyperfine fields in ordered FeCo and in a random antiferromagnetic Fe0.65Mn0.35 alloy are presented. In FeCo, Sn atoms apparently strongly prefer to enter the Co site where they exhibit a large hyperfine field (−268 kG at 0°K) which decreases considerably faster with temperature than does the host magnetization. The average Sn119 hyperfine field in Fe‐Mn is also large (∼175 kG at 0°K) and decreases in an approximately linear fashion with T2.