Thickness and Temperature Dependence of Exchange Bias in Co/CoO Bilayers

• DOI: 10.1007/s10948-011-1226-1
• Publication Date: 2011-08-04T03:33:06Z
• Authors: E. Demirci; M. Öztürk; R. Topkaya; S. Kazan; N. Akdoğan; M. Obaida; K. Westerholt
• Keywords: 0103 physical sciences; 01 natural sciences

The effects of the ferromagnetic (FM) Co layer thickness on magnetic anisotropies and exchange bias (EB) properties of Co/CoO bilayers have been investigated by using ferromagnetic resonance (FMR) and vibrating sample magnetometer (VSM) techniques. The temperature and thickness dependence of EB were studied in temperature range of 4–320 K. FMR and VSM measurements show that Co/CoO bilayers exhibit negative exchange bias just below the blocking temperature (T B). Room-temperature in-plane FMR measurements reveal that the Co layer was epitaxially grown on MgO substrate with four-fold magneto-crystalline symmetry. The data also show that the easy axis of magnetization is in the film plane and parallel to the 〈110〉 crystallographic directions of MgO substrate in all samples.