Tailoring interfacial exchange coupling with low-energy ion beam bombardment: Tuning the interface roughness

Abstract

By ascertaining NiO surface roughness in a Ni80Fe20/NiO film system, we were able to correlate the effects of altered interface roughness from low-energy ion-beam bombardment of the NiO layer and the different thermal instabilities in the NiO nanocrystallites. From experiment and by modelling the temperature dependence of the exchange bias field and coercivity, we have found that reducing the interface roughness and changing the interface texture from an irregular to striped conformation enhanced the exchange coupling strength. Our results were in good agreement with recent simulations using the domain state model that incorporated interface mixing. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3697405

Correlating Uncompensated Antiferromagnetic Moments and Exchange Coupling Interactions in Interface Ion-Beam Bombarded Co90Fe10/CoFe-Oxide Bilayers

“…Our previous work on NiFe/NiO bilayers [21] has shown that the pure ferromagnetic (e.g., permalloy) layer usually exhibited identical ZFC and FC curve with H app = 100 Oe The degree of exchange coupling is qualitatively estimated by the difference in magnetization (Δ) [29] between FC and ZFC at 50 K, which is about 3% in a spin (or cluster) glass [30] and about 0.5% in a pure permalloy layer [29] …”

“…The Co 90 Fe 10 (at%) / CoFe-oxide bilayers were prepared on oxidized Si wafer substrates by using a dual ion-beam sputtering deposition technique [21,22]. A Kaufman ion source (800 V, 7.5 mA) was used to focus an Argon ion-beam onto a commercial To study exchange bias effects, the Co 90 Fe 10 / CoFe-oxide bilayers were 12 kOe field-cooled from 350 to 50 K. The hysteresis loops for the films after field cooling are shown in Fig.…”

The effects of interfacial interactions between Fe–O and Fe–Si induced by ion-beam bombardment on the magnetic properties of Si-oxide/Fe bilayers

“…Ion-beam bombardment is commonly used in the preparation and investigation of magnetic thin films to alter the interface roughness [17], crystalline structures [18], domain structures [19], and to tailor the chemical composition [20]. The structural and compositional changes could be easily tailored by adjusting the ion-beam voltage [21] or reactive-gas content [22].…”

Correlating Uncompensated Antiferromagnetic Moments and Exchange Coupling Interactions in Interface Ion-Beam Bombarded Co90Fe10/CoFe-Oxide Bilayers

“…Exchange bias [1][2][3][4][5][6], i.e., the shift of the hysteresis loop of a ferromagnetic (FM) material in contact with an antiferromagnetic (AFM) material after a field-cooling process, depends on many factors including the particular materials involved [7][8][9][10], film growth conditions [11][12][13][14], the structural, compositional and magnetic details of the interfaces [15][16][17][18], the magnetic stiffness of the AFM moments, and the field-cooling conditions [19][20][21][22].…”