The effect of Bi additives on the properties of Fe-Pt films

  • V. F. Bashev Oles Honchar Dnipro National University, Dnipro, Ukraine
  • N. A. Kutseva Oles Honchar Dnipro National University, Dnipro, Ukraine
  • O. I. Kushnerov Oles Honchar Dnipro National University, Dnipro, Ukraine
  • S. I. Ryabtsev Oles Honchar Dnipro National University, Dnipro, Ukraine
  • O. V. Yelina Oles Honchar Dnipro National University, Dnipro, Ukraine
  • O. O. Veres Oles Honchar Dnipro National University, Dnipro, Ukraine
Keywords: thin film, ion-plasma sputtering, coercive force, metastable state, amorphous and crystalline phases

Abstract

Using the modernized three-electrode ion-plasma sputtering method, homogeneous thin films of FePt and Fe (Pt/Bi) were obtained. Films were deposited on NaCl and glass-ceramic substrates. The film thickness was 120-530 nm. In this case, the calculated cooling rate reached ~ 1012–1014 K/s. The structure of the FePt and Fe (Pt/Bi) films was investigated using X-ray diffraction and electron microscopy methods. It was established that metastable phases were formed in freshly sputtered films, including a supersaturated solid solution, a nanocrystalline and amorphous phases. It was determined that the obtained metastable structures are stable when heated to 540-880 K, depending on the composition. It was established that Bi additives significantly reduce the coercive force of films in the as-sputtered state. It was shown that a heat treatment increased the coercive force up to 36 kA/m in FePt films and up to 10 kA/m in Fe (Pt/Bi) films. The composition of Fe (Pt/Bi) films with a small value of the temperature coefficient of resistance (TCR ~3·10-5 K-1) was determined.

Published
2019-12-27
Section
Articles