|
|||||
|
|
Crystal structure and compressibility of FePt nanoparticles under high pressures and high temperatures |
|
| Authors: | Wei Qiu Gregory B. Thompson Shifan Shi |
| Affiliation: | 1. Department of Physics , University of Alabama at Birmingham (UAB) , Birmingham, AL, 35294-1170, USA;2. Department of Metallurgical and Materials Engineering, The Center for Materials for Information Technology (MINT) , The University of Alabama , Box 870202, Tuscaloosa, AL, 35487, USA;3. Department of Physics, The Center for Materials for Information Technology (MINT) , The University of Alabama , Box 870324, Tuscaloosa, AL, 35487, USA |
| Abstract: | FePt nanoparticles with an average grain size of 4 nm and equiatomic composition of Fe and Pt was studied under high pressures in a diamond anvil cell to investigate its structural stability and compressibility under high compression. The ambient pressure disordered face-centered-cubic (fcc) phase was found to be stable to the highest pressure of 61 GPa (compression of 15%) at room temperature. The compression of Fe50Pt50 nanoparticles is closer to the compression curve for pure Pt and shows lower compressibility than what would be expected for a bulk Fe50Pt50 alloy. The nanoparticle character of Fe50Pt50 sample is maintained to the highest pressure without any observable grain coarsening effects at ambient temperature. Laser heating of disordered fcc phase at 32 GPa to a temperature of 2000 K resulted in a phase transformation to a microcrystalline phase with the distorted fcc structure. |
| Keywords: | Nanoparticles Iron–Platinum alloys Phase transformations Compressibility |