Effects of Ag addition on FePt L10 ordering transition: A direct observation of ordering transition and Ag segregation in FePtAg alloy films

Lei Wang, Tenghua Gao, Youxing Yu

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

FePt and (FePt)91.2Ag8.8 alloy films were deposited by magnetron sputtering. The average coercivity of (FePt)91.2Ag8.8 films reaches 8.51 × 105 A/m, which is 0.63 × 105 A/m higher than that of the corresponding FePt films. Ag addition effectively promotes the FePt L10 ordering transition at a relatively low annealing temperature of 400°C. The promotion mechanism was investigated by using in situ high-resolution transmission electron microscopy (HRTEM) and ex situ X-ray absorption fine structure (XAFS). The concurrence of ordering transition and Ag segregation in FePtAg alloy films was first observed by using in situ heating HRTEM. The time-resolved evolution reveals more details on the role of Ag addition in FePt low-temperature ordering. Ex situ XAFS results further confirm that Ag replaces Fe sites in the as-deposited films and segregates from FePt-Ag solid solution phase through annealing at elevated temperatures. The segregation of Ag atoms leaves vacancies in the grain. The vacancy formation is believed to accelerate the diffusion of Fe and Pt atoms, which is critical for the L10 ordering transition.

Original languageEnglish
Article number235304
JournalJournal of Applied Physics
Volume118
Issue number23
DOIs
Publication statusPublished - 2015 Dec 21
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Effects of Ag addition on FePt L1<sub>0</sub> ordering transition: A direct observation of ordering transition and Ag segregation in FePtAg alloy films'. Together they form a unique fingerprint.

  • Cite this