Pd2TiAl : Fe-57 investigated by monochromatic, circularly polarized Mossbauer source

The Heusler alloy Pd2TiAl is claimed to exhibit magnetic order with a relat ively high transition temperature and a small magnetic moment, of the order of a hundredth of Bohr magneton. Fe-57 impurity was admired into the alloy in order to carry out Mossbauer measurements with circularly polarized mon ochromatic radiation. The results show that most iron atoms are located on Ti or Al sites surrounded by eight Pd atoms while a small part occupies Pd sites. An external magnetic field applied to the sample induces an addition al field acting on the Fe-57 nucleus. The induced field direction is parall el to the external field and originates from conduction electron polarizati on. An upper limit for the static hyperfine-field intensity was determined to be about 5 x 10(-2) T in zero-applied field and room temperature. The fl uctuating hyperfine field of the order of a tenth of tesla is considered as a mechanism responsible for the observed line broadening. (C) 1999 Elsevie r Science B.V. All rights reserved.