Moessbauer studies of 155Tb sources produced by recoil implantation in iron and nickel

As part of a program to study the hyperfine interaction of rare earth impurities in ferromagnetic metals we have produced 155Tb sources (Tsub(1/2)=5.6d) to study the 5/2-→3/2- 86.5 keV Moessbauer transition in 155Gd. Unlike in the other rare earths, the Gd hyperfine field has no orbital contribution, thus enabling the study of the contact contribution into some detail. Moreover, this study was set up as a first exploration of the merits of the recoil implantation technique for the production of Moessbauer sources of (rather) short lived isotopes