We present the results of a study related to phase transformation of chemically synthesized FePt nanoparticles under high pressure from face-centered cubic into face-centered tetragonal structure. As-synthesized nanoparticles are around nm and show superparamagnetic behavior at 300 K. After annealing under 60 bar pressure of hydrogen at 400◦C for 2 h, nanoparticles exhibit strong ferromagnetic behavior with 5391 Oe coercivity. Results show that highpressure annealing lowers the decomposition temperature of the surfactants surrounding nanoparticles and partially hinders agglomeration arising from heat treatment. |
