Low-temperature FCC to L10 phase transformation in CoPt(Bi) nanoparticles

Authors

Frank M. Abel, University of Delaware
Vasilis Tzitzios, NCSR
David J. Sellmeyer, University of Nebraska
George C. Hadjipanayis, University of Delaware

Date of this Version

2016

Citation

AIP Advances 6, 056013 (2016)

Comments

© Author(s) 2016.

https://doi.org/10.1063/1.4943932

Abstract

This work is focused on the effects of Bi substitution on the synthesis of CoPt nanoparticles with the L1₀ structure using a modified organometallic approach. The structural and magnetic properties of the nanoparticles have been studied and compared directly with those of CoPt nanoparticles synthesized by the same tech- nique but in the absence of Bi substitution. The as-synthesized particles at 330 ◦C have an average size of 11.7 nm and a partially ordered L10 phase with a coercivity of 1 kOe. The coercivity is increased to 9.3 kOe and 12.4 kOe after annealing for 1 hour at 600 and 700 ◦C. The structural and magnetic properties suggest that Bi promotes the formation of ordered L1₀ phase at low temperatures leading to the development of high coercivities.