Magnetism of Cr-Doped Diamond-Like Carbon

Authors

• J. A. Colón Santana, University of Nebraska-Lincoln
• Ralph Skomski, University of Nebraska-LincolnFollow
• V. R. Singh, Louisiana State University, Baton RougeFollow
• V. Palshin, Louisiana State University, Baton Rouge
• A. Petukhov, South Dakota School of Mines
• Yaroslav B. Losovyj, Louisiana State University at Baton RougeFollow
• Andrei Sokolov, University of Nebraska-LincolnFollow
• Peter A. Dowben, University of Nebraska-LincolnFollow
• Ihor Ketsman, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2009

Comments

Published in JOURNAL OF APPLIED PHYSICS 105, 07A930 (2009). Copyright © 2009 American Institute of Physics. Used by permission.

Abstract

Chromium-doped hydrogenated diamond-like carbon (Cr-DLC) and chromium carbide hydrogenated DLC alloys were synthesized by plasma-assisted vapor deposition and investigated by x-ray absorption near edge structure spectroscopy, extended x-ray absorption fine structure, and superconducting quantum interference device (SQUID) magnetometry. Structural and magnetic properties of the doped and alloy materials were investigated as a function of the Cr concentration (0.1–20 at. %). Toward the upper end of the concentration range, Cr precipitates in the form of chromium carbide (Cr₃C₂) nanoclusters. For low Cr concentrations, the systems are ferromagnetic at very low temperatures, whereas the chromium carbide clusters appear to be antiferromagnetic with uncompensated spins at the surface. Cr-DLC films and alloys with various Cr concentrations are used to make heterojunctions on silicon, and the produced diodes are investigated by I-V measurements. The heterojunctions exhibit negative magnetoresistance that saturates at less than 500 Oe and may be suitable for spin-electronics applications.