Journal of Magnetism and Magnetic Materials 242–245 (2002) 317–320 Perpendicularly oriented FePt nanoparticles sputtered on heated substrates Y. Huang a, *, H. Okumura a , G. C. Hadjipanayis a , D. Weller b a Department of Physics and Astronomy, University of Delaware, Newark, Delaware DE 19716, USA b Seagate Technology, Pittsburgh, PA 15203, USA Abstract Textured FePt/C nanocomposite films have been deposited onto heated substrates at a temperature up to 6501C. At ambient substrate temperature, FePt and carbon form a multilayered structure with a disordered FCC structure which is magnetically soft. Post-annealing in the range of 550–7501C leads to the formation of ordered FePt particles. FePt nanoparticles with strong perpendicular texture were obtained by depositing directly onto heated substrates at a temperature above 4501C. TEM data show well-separated FePt particles of unique elongated shape with the major axis (B20nm) oriented in a direction perpendicular to the film. The development of the texture is controlled by both the substrate temperature and bilayer film thickness. Kelly Henkel plots indicate small interactions between the particles in both the parallel and perpendicular directions. r 2002 Elsevier Science B.V. All rights reserved. Keywords: Magnetic recording media; Nanoparticles; Thin filmFsputtered; Texture 1. Introduction Perpendicular recording media attracted much atten- tion recently regarding future recording since they show advantages over longitudinal media with better signal- to-noise ratio (SNR) as the particle size becomes smaller [1,2]. FePt films with perpendicular texture were obtained by the epitaxial growth technique [3–6] by using conventional sputtering with certain restrictions on film thickness [7]. In this study, we present a different method to fabricate ordered FePt nanoparticles with strong perpendicular texture by depositing FePt and C onto heated substrates. The development of texture was investigated as a function of the substrate temperature and different bilayer thicknesses. The origin of the texture was explained by the structure morphology of the FePt particles. 2. Experimental The FePt/C films were deposited by DC magnetron sputtering from solid FePt and Carbon targets onto Si (111) substrates using the tandem deposition technique. The base pressure of the chamber was 2  10 7 Torr and a high purity Argon gas flow with a pressure of 5mTorr was used during sputtering. The substrate was attached to a ceramic heater with temperature adjustable up to 6501C. A 200 ( A layer of carbon was used as underlayer and overlayer to encapsulate FePt/C multilayers in order to reduce any effect from the substrate and to avoid oxidation during annealing. The structure of the films was examined with a Jeol JEM-2000 FX TEM transmission electron microscope and a Philips CM20 XRD. 3. Results and discussion The as-made FePt nanoparticles prepared at an ambient substrate temperature showed amorphous-like structure, as reported previously [8]. However, ordered FCT FePt particles were obtained directly by sputtering *Corresponding author. Tel.: +1-302-831-3515; fax: +1- 302-831-1637. E-mail address: hyh@udel.edu (Y. Huang). 0304-8853/02/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0304-8853(01)01227-6