Preparation ofL10ordered FePd, FePt, and CoPt thin films with flat surfaces on MgO(001) single-crystal substrates

Akira Itabashi,Mitsuru Ohtake,Masaaki Futamoto,Fumiyoshi Kirino,Shouhei Ouchi,P Tiberto,G Gubbiotti,C De Julián Fernández,P Vavassori,F Casoli,M Solzi,M Affronte,S Tacchi,C Marquina,F Pratt

doi:10.1051/epjconf/20134007001

Abstract

FePd, FePt, and CoPt alloy thin films are prepared on MgO(001) single-crystal substrates by employing a two-step method consisting of sputter deposition at low-temperature (room temperature) followed by high-temperature annealing at 600 °C. FePd, FePt, and CoPt single-crystal films with disordered structure (A 1) grow epitaxially on MgO substrates at room temperature. By annealing these disordered films at 600 °C, a transformation from A 1 to L 10 -ordered phase occurs. The order degrees of annealed FePd, FePt, and CoPt films are 0.63, 0.38, and 0.16, respectively. The films before annealing have very flat surfaces and the flat surfaces are kept after annealing. The arithmetical mean surface roughness values of annealed FePd, FePt, and CoPt films are 0.3, 0.1, and 0.2 nm, respectively. The two-step method is considered to be useful for preparation of FePd, FePt, and CoPt alloy thin films with flat surfaces, which are necessary for practical applications.

Highlights

L10 ordered alloy thin films with high uniaxial magnetocrystalline anisotropy energies (Ku) such as FePd, FePt, and CoPt have been investigated for applications like perpendicular magnetic recording media, perpendicularly magnetized magnetoresistance random access memory devices, etc
L10 ordered FePd alloy epitaxial films with very flat surfaces were realized on MgO single-crystal substrates of (001), (110), and (111) orientations by using a two-step method, low-temperature deposition at 200 °C followed by high-temperature annealing at 600 °C [8]
Figures 1(a-1) and (a-2) show the reflection high-energy electron diffraction (RHEED) patterns observed for an FePd film deposited at room temperature (RT) and the film annealed at 600 °C after deposition at RT, respectively

Summary

Introduction

L10 ordered alloy thin films with high uniaxial magnetocrystalline anisotropy energies (Ku) such as FePd, FePt, and CoPt have been investigated for applications like perpendicular magnetic recording media, perpendicularly magnetized magnetoresistance random access memory devices, etc. For such practical applications, realization of very flat surface is required in addition to achievement of high order degree and control of the c-axis direction. L10 ordered FePd alloy epitaxial films with very flat surfaces were realized on MgO single-crystal substrates of (001), (110), and (111) orientations by using a two-step method, low-temperature deposition at 200 °C followed by high-temperature annealing at 600 °C [8]. The detailed structure and the magnetic properties of these films are compared

Methods

Results

Conclusion