AVS 51st International Symposium
    Magnetic Interfaces and Nanostructures Friday Sessions
       Session MI-FrM

Paper MI-FrM11
Characterization of FePt-based Magnetic Nanocomposite Thin Films Prepared by Pulsed Filtered Vacuum Arc Deposition

Friday, November 19, 2004, 11:40 am, Room 304A

Session: Advanced Magnetic Data Storage and Thin Film Processing
Presenter: Y.W. Lai, Chinese University of Hong Kong
Authors: Y.W. Lai, Chinese University of Hong Kong
M.F. Chiah, Chinese University of Hong Kong
N. Ke, Chinese University of Hong Kong
Q. Li, Chinese University of Hong Kong
W.Y. Cheung, Chinese University of Hong Kong
S.P. Wong, Chinese University of Hong Kong
Correspondent: Click to Email
We have prepared FePt-X (X = C, Cu or Ag) nanocomposite thin films of various compositions consisting of FePt grains embedding in carbon, copper or silver matrices using a pulsed filtered vacuum arc deposition technique. In addition to usual co-deposition processes, another process was adopted where multilayers of the three elemental components with an appropriate design of thickness and sequence were first deposited followed by a rapid thermal annealing (RTA) in an argon atmosphere. Characterization of these films was performed using Rutherford backscattering spectrometry, x-ray diffraction, transmission electron microscopy, and vibrating sample magnetometry. The dependence of the structure and magnetic properties, such as the phase and size of the magnetic grains and the coercivity of these films, on the deposition parameters, annealing conditions and the matrix materials were studied in details. Both x-ray diffraction and transmission electron microscopy analyses confirmed the formation of L1@sub 0@ phase FePt nano-grains after appropriate annealing. For example, for the film with a particular composition of Fe@sub 43@Pt@sub 45@Cu@sub 12@, the L1@sub 0@ phase formation was observed after the RTA process at 400@super o@C, and the film exhibited a coercivity of 6.5 kOe. Compared to films prepared by usual co-deposition process, those films prepared using the multilayer deposition approach see a significant lowering in the ordering temperature at which the L1@sub 0@ phase started to form. The degree of lowering in the ordering temperature was seen to depend on the species of the matrix material. It is believed that different mechanisms are responsible for such ordering temperature lowering in films of different matrices. This work is supported in part by the Research Grants Council of Hong Kong SAR (Ref. Number: CUHK4216/00E).