Correlating Uncompensated Antiferromagnetic Moments and Exchange Coupling Interactions in Interface Ion-Beam Bombarded Co$_{90}$Fe$_{10}$/CoFe-Oxide Bilayers

Chin Shueh, Pei-Shi Chen, David Cortie, Frank Klose, Wen-Chen Chen, Te-Ho Wu, Johan van Lierop, Ko-Wei Lin
2012 Japanese Journal of Applied Physics  
The coercivity and exchange bias field of ferro-/antiferromagnetic Co 90Fe10/CoFe-oxide bilayers were studied as function of the surface morphology of the bottom CoFe-oxide layer. The CoFe-oxide surface structure was varied systematically by low energy (0-70 V) Argon ion-beam bombardment before subsequent deposition of the Co90Fe10 layer. Transmission electron microscopy results showed that the bilayer consisted of hcp Co90Fe10 and rock-salt CoFe-oxide. At low temperatures, enhanced
more » ... nhanced coercivities and exchange bias fields with increasing ion-beam bombardment energy were observed, which are attributed to defects and uncompensated moments created near the CoFe-oxide surface in increasing amounts with larger ion-beam bombardment energies. Magnetometry results also showed an increasing divergence of the low field temperature dependent magnetization [ΔM(T)] between field-cooling and zero-field-cooling processes, and an increasing blocking temperature with increasing ion-beam bombardment energy. Abstract The coercivity and exchange bias field of ferro-/antiferromagnetic Co 90 Fe 10 / CoFe-oxide bilayers were studied as function of the surface morphology of the bottom CoFe-oxide layer. The CoFe-oxide surface structure was varied systematically by low energy (0 -70 V) Argon ion-beam bombardment before subsequent deposition of the Co 90 Fe 10 layer. Transmission electron microscopy results showed that the bilayer consisted of hcp Co 90 Fe 10 and rock-salt CoFe-oxide. At low temperatures, enhanced coercivities and exchange bias fields with increasing ion-beam bombardment energy were observed, which are attributed to defects and uncompensated moments created near the CoFe-oxide surface in increasing amounts with larger ion-beam bombardment energies. Magnetometry results also showed an increasing divergence of the low field temperature dependent magnetization [ΔM(T)] between field-cooling and zero-field-cooling processes, and an increasing blocking temperature with increasing ion-beam bombardment energy.
doi:10.1143/jjap.51.11pg02 fatcat:isknw6kmzzge5lgqtat723mbj4