Synthesis of highly ordered L10 MPt alloys (M = Fe, Co, Ni) from crystalline salts: an in situ study of the pre-ordered precursor reduction strategy

Abstract

The synthesis of highly ordered magnetic L1₀ alloys by means of the so-called pre-ordered precursor reduction (PPR) approach is deeply investigated by in situ X-ray absorption spectroscopy experiments. By following the chemical and structural evolution of the M(H₂O)₆PtCl₆ (M = Fe, Co, Ni) precursor salts during hydrogen-assisted thermal reduction, it was possible to shed light on the key role of the crystalline initial compound whose intrinsic atomic order serves as a driving force to kinetically favor the formation of highly ordered FePt, CoPt and NiPt L1₀ alloys under milder conditions with respect to ordinary thermal treatments. The results confirm the potentiality of the PPR synthesis approach that can be suitably extended, by properly choosing the precursor salt, for the synthesis of other binary and ternary alloys where the chemical order represents a key property of the material, with a potential strong impact on several technological applications.