The origin of enhanced L10 chemical ordering in Ag-doped FePt nanoparticles

Magnetic properties and microstructure of (001) oriented Ag/FePt, Ag/FePt/Ag films

“…The activation energy decreased is due to the increased in vacancies concentration and thus the diffusion coefficient of Fe and Pt atoms. The diffusion coefficient of Fe, Pt atoms in Agdoped FePt particles is approximated 3 × 10 3 timers higher than the pure FePt at 400 • C [17]. The fast ordering and recrystallization was required in this study to obtain [0 0 1] oriented FePt films.…”

“…The diffusion coefficient (D) and vacancies concentration (X vac ) were approximated by Arrhenius relationship, D ∝ X vac ∝ exp[−Q vac /(RT)], where Q vac is the activation energy for vacancy formation [17]. The 20%Ag-doped FePt particles shows the lower activation energy compared to the pure FePt particle [17]. The activation energy decreased is due to the increased in vacancies concentration and thus the diffusion coefficient of Fe and Pt atoms.…”

“…The A1 to L1 0 phase transformation in the FePt nanoparticles and films are a diffusion-based reaction. The diffusion coefficient (D) and vacancies concentration (X vac ) were approximated by Arrhenius relationship, D ∝ X vac ∝ exp[−Q vac /(RT)], where Q vac is the activation energy for vacancy formation [17]. The 20%Ag-doped FePt particles shows the lower activation energy compared to the pure FePt particle [17].…”

“…The FePt film with Ag doping, Ag buffer layer [14], capped Ag layer, and (FePt/Ag) n multilayer were discussed to decrease the ordering temperature, to form the particulate structure and enhance the coercivity. The added Ag was reported to promote ordering due to vacancies formation during immiscible Ag atom repulsive from the FePt particles [15][16][17]. The Ag layer was also reported either immiscible or dissolve in FePt phase [18,19].…”

Enhanced magnetic properties of FePt nanoparticles codeposited on Ag nanoislands

“…7,8 More recently, introducing immiscible metallic additives, such as Au, Cu, and Ag, [9][10][11][12][13][14] has been shown to promote the ordering transformation at lower T s , by providing a decrease in the activation energy. 10 Until now, this concept has been demonstrated only on nanoparticles 9,11,12,14 synthesized with chemical methods on thin films 10 and on multilayer structures. 14 While thin film deposition methods are ubiquitous in a wide range of nanomaterial technologies, mainly because of their simplicity and flexibility, but also because of their high yields in industrial processes, there is no evidence in the literature of free standing Ag/FePt nanoparticles prepared using such techniques.…”