Local susceptibilities in the paramagnetic regime of Y(Fe,Al)₂

The local susceptibilities of Y(Fe,Al)₂ are determined by high-field ⁵⁷Fe Mossbauer measurements and are compared with the results of ASW and LAPW band-structure calculations. The effective field acting on the ⁵⁷Fe nuclei arises not only from the applied field but also from core and valence contributions, with opposite signs. With decreasing Fe concentration the valence contribution increases and reaches a magnitude comparable with the core contribution which remains nearly constant. The local susceptibility stays about the same when Fe is surrounded mainly by Al but increases for more than three nearest Fe neighbours, indicating that Fe carries a magnetic moment even when it is completely surrounded by Al. The Mossbauer results are in excellent agreement with the effective Fe moments derived from bulk magnetization measurements.