Structural Dependent Ferromagnetic-Nonmagnetic Phase Change in FePtRu Films

Abstract

Herein, we studied correlations between crystal structures and magnetic properties of FePt 1− Ru films. At room temperature, the chemical disordered 1 films with 0 ≤ < 0.20 and 0.20 ≤ ≤ 1.00 exhibited ferromagnetic properties and paramagnetic properties, respectively. Curie temperature of the disordered film with = 0.30 was 200 K. In contrast, the ordered 1 0 films had ferromagnetic properties in a wider range of 0 ≤ < 0.80 with the magnetic easy-axis perpendicular to the film plane. For 0 ≤ ≤ 0.50, with the ordered structure, the films had high magnetization and high uniaxial magnetic anisotropy of over 10 7 erg cm −3 . For = 0.60-0.70 with the ordered structure, a temperature-dependent magnetic phase transition appeared, and magnetization reached its maximum value at around 200 K. Using this material system, we proposed a nanopatterning method involving a ferromagnetic-paramagnetic phase change due to the ordered-disordered structural transformation.

Synthesis of a High-Coercivity FePt–Ag Nanocomposite Magnet via Block Copolymer-Templated Self-Assembly

“…Sputtering is the most commonly used method for fabricating FePt nanostructures [14][15][16][17][18], but this method, which requires high vacuum and high energy, is too expensive for industrial applications. Fabrication of FePt nanostructures by chemical synthesis is a promising alternative, but achieving high coercivity with chemical synthesis methods has been difficult [19][20][21][22].…”