Cu induced low temperature ordering of fct-FePtCu nanoparticles prepared by solution phase synthesis

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 7; no. 37; pp. 11632 - 11638
• Main Authors: Lei, Wenjuan, Yu, Yongsheng, Yang, Weiwei
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2019
• Subjects: Coercivity; Copper; Diffusion; Doping; Intermetallic compounds; Iron compounds; Low temperature; Magnetic properties; Nanoparticles; Phase transitions; Platinum compounds; Synthesis
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c9tc03961a

Here, we report simple one-step solution phase synthesis for face-centered tetragonal FePtCu nanoparticles (NPs). Cu atoms are doped into the FePt lattice during synthesis, occupying Fe sites to form FePtCu alloy NPs. The phase and magnetic properties of the NPs can then be altered by varying the reaction conditions. We report room-temperature coercivities as high as 5.09 kOe for FePtCu NPs synthesized at 310 °C, significantly higher than the coercivity of pure FePt NPs without Cu doping. We suggest that Cu incorporation into the FePt lattice is responsible for the observed ordering enhancement of the as-prepared NPs, specifically increasing atomic diffusivity during the fcc-to-fct phase transformation. Our findings provide critical insights the effects Cu doping, namely its role in inducing atomic rearrangement and phase transformation of FePt NPs at low synthesis temperatures. Cu doping can occupy the Fe sites in the FePt lattice, contract c axis and increase atom diffusivity, favoring atoms rearrangement and phase transformation from fcc to fct at lower temperature.