Manifestations of Spinodal Decomposition into Dilute Pd$_{1-x}$Fe$_{x}$ "Phases" in Iron-Implanted Palladium Films: FMR Study

TL;DR

This study uses FMR and VSM techniques to investigate palladium-iron films implanted with iron ions, revealing that the system tends to undergo spinodal decomposition into multiple magnetic phases rather than forming a homogeneous alloy.

Contribution

It demonstrates the tendency of Pd-Fe alloys to decompose into distinct magnetic phases after ion implantation and annealing, challenging the expectations from the phase diagram.

Findings

Multiple FMR responses depend on iron dose.

Annealing does not produce a homogeneous alloy.

Evidence of spinodal decomposition into magnetic phases.

Abstract

Palladium-iron alloys produced by high-dose implantation of iron ions into epitaxial palladium films were investigated with the ferromagnetic resonance (FMR) and vibrating sample magnetometry (VSM) techniques. The samples reveal distinct multiple FMR responses depending on the dose of iron ion implantation. The post-implantation annealing at 770 K does not bring the implanted films to a homogeneous solid solution state, as might be expected from the Pd-Fe phase diagram. On the contrary, the system approaches a stable state composed of several magnetic phases. FMR spectra exhibit an angular behavior specific for a stack of interacting magnetic layers. This observation, correlated with the magnetometry data, indicates that the palladium-iron binary alloy has a previously unknown tendency towards spinodal decomposition into isostructural phases with well-defined iron concentrations and, accordingly, with different temperatures of ferromagnetic ordering and saturation magnetizations.