Long-Range Effects in the FePd₂Au Alloy Under Ion Bombardment

The effect is studied of ion bombardment (Ar⁺, E = 20 keV, j = 100 A/cm², F = 5 × 10¹⁶ to 10¹⁸ cm^-2) and thermal annealing on the atomic and magnetic structure of the FePd₂Au alloy after 80% cold plastic deformation and quenching from 1200°C. It is established by the Mössbauer effect and X-ray diffraction that ion irradiation at 350°C (for 1.5 to 30 min) causes formation in the disordered face-centered-cubic matrix of a long-range atomic order (of an Fe atom sublattice at an anomalously large depth up to 20 m, at an ion projected range of ~13 nm) accompanied by ferromagnetic to asperomagnetic phase transition (T_meas = 77 K). Annealing at T = 350°C up to 30 min in the absence of irradiation does not result in any noticeable changes in the atomic and magnetic structure. Atom mobility (the ordered structure formation rate) in the course of irradiation at 350°C is approximately the same as observed in the case of annealing at 700°C.