Phase transition of chemically synthesized FePt nanoparticles under high pressure


ŞİMŞEK T., Karci O., ÖZCAN Ş.

TURKISH JOURNAL OF CHEMISTRY, vol.42, no.5, pp.1217-1223, 2018 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 42 Issue: 5
  • Publication Date: 2018
  • Doi Number: 10.3906/kim-1711-57
  • Title of Journal : TURKISH JOURNAL OF CHEMISTRY
  • Page Numbers: pp.1217-1223

Abstract

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 4.5 nm and show superparamagnetic behavior at 300 K. After annealing under 60 bar pressure of hydrogen at 400 degrees C for 2 h, nanoparticles exhibit strong ferromagnetic behavior with 5391 Oe coercivity. Results show that high-pressure annealing lowers the decomposition temperature of the surfactants surrounding nanoparticles and partially hinders agglomeration arising from heat treatment. The promising ferromagnetic properties of the FePt nanoparticles after annealing under high pressure make them suitable for ultrahigh-density memory devices.