Magnetic hardening in FePt nanostructured films

Authors

• J. Ping Liu, University of Nebraska-LincolnFollow
• Yi Liu, University of Nebraska-LincolnFollow
• C.P. Luo, University of Nebraska - Lincoln
• Z.S. Shan, University of Nebraska - Lincoln

Document Type

Article

Date of this Version

4-15-1997

Comments

Published by American Institute of Physics. J. Applied Physics 81, 5644 (1997). ©1997 American Institute of Physics. Permission to use. http://jap.aip.org/jap/.

Abstract

FePt films have been prepared by sputtering Fe/Pt multilayers onto glass or silicon substrates. The thickness of the Fe and Pt layers was adjusted with the Fe:Pt atomic ratio from about 1:1 to 2:1. Magnetic hardening is observed after heat treatment at elevated temperatures, which led to coercivity values exceeding 20 kOe in samples with an Fe:Pt ratio around 1.2:1. The hardening originates from the formation of the tetragonal FePt phase with high magnetocrystalline anisotropy and a favorable microstructure. Two-phase composite films containing hard and soft phases were obtained when the Fe:Pt ratio increased. Under optimized processing conditions, composite films with energy products larger than 30 MG Oe at room temperature have been successfully produced.