Magnetic coupling in Co/Cr₂O₃/CrO₂ "trilayer" films

Authors

Ruihau Cheng, University of Nebraska-Lincoln
A. N. Caruso, University of Nebraska-LincolnFollow
Lu Yuan, University of Nebraska-LincolnFollow
Sy_Hwang Liou, University of Nebraska-LincolnFollow
Peter A. Dowben, University of Nebraska-LincolnFollow

Date of this Version

March 2003

Comments

Published Applied Physics Letters 82 (2003) 1443-1445. Permission to use.

Abstract

The ferromagnetic coupling between Co and CrO₂ , through an insulator (Cr₂O₃) was characterized by in situ magneto-optic Kerr effect. By evaporating 20–60 Å Co thin films on top of epitaxial CrO₂ films, a Co/Cr₂O₃ /CrO₂ trilayer system can be readily fabricated; this is possible because the native surface layer of CrO₂ is Cr₂O₃ . In situ x-ray photoemission studies show that the Co is oxidized at the interface between Co and Cr₂O₃ , so that the system more resembles Co/CoO/Cr₂O₃ /CrO₂ . The Co thickness and temperature dependence of the magnetic hysteresis loops indicate that magnetic coupling strength increases with increasing Co thickness and decreases with increasing temperature. The magnetic coupling through the insulator barrier may be related to defect states in the insulating barrier layer. © 2003 American Institute of Physics.