Direction dependent giant magnetoresistance of spin valves using epitaxial Cr 2O 3 as the pinning layer
Abstract
We report the direction dependent magnetization and the giant magnetoresistance (GMR) data for the spin valves NiFe/Cu/NiFe/Cr 2O 3. The sample with the (1 1¯ 0 2) Cr 2O 3 showed typical spin valve properties after the magnetic field annealing (MFA) parallel to the [1¯ 1 1] direction; the exchange bias of ∼7 0 0 Oe and the highly asymmetric GMR effect of ∼4% with the magnetic field sweep. However, the MFA perpendicular to the [1¯ 1 1] direction induced a symmetric GMR effect of ∼2.6% without exchange bias. It is noticeable that the interface exchange coupling constant J by the (1 1¯ 0 2) Cr 2O 3 is maximally ∼0.27 erg/cm2. On the other hand, the sample with the (1 0 1¯ 0) Cr 2O 3 showed no exchange bias in all directions but it displayed a symmetric GMR effect of 1.8-3.5% which was caused by a coercivity difference between two NiFe layers.
- Publication:
-
Journal of Magnetism and Magnetic Materials
- Pub Date:
- March 2007
- DOI:
- 10.1016/j.jmmm.2006.10.1066
- Bibcode:
- 2007JMMM..310.1892D