Current-in-plane giant magnetoresistance: The effect of interface roughness and spin-depolarization due to the proximity of a buffer layer

• Published in: Journal of magnetism and magnetic materials Vol. 307; no. 2; pp. L1 - L6
• Main Authors: Breidbach, M., Bürgler, D.E., Grünberg, P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2006; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Giant magnetoresistance; GMR; Interface roughness; Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED); Magnetic properties and materials; Magnetotransport phenomena, materials for magnetotransport; Physics; Proximity effect; RHEED oscillations; Spin polarization; 68.35.Ct; 75.70.−i; Spin polarization; Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED); Proximity effect; 75.47.De; 61.14.Hg; GMR; Interface roughness; RHEED oscillations; Buffer layer; Gold; 75.70.-i; Roughness; Oscillations; Iron; Giant magnetoresistance; RHEED; Spin depolarization; Thickness; Interfaces; Layer by layer growth; Multilayers; Chromium; LEED
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2006.04.020

We report on proximity effects of a Au buffer layer on the current-in-plane giant magnetoresistance effect (CIP-GMR) in high-quality, epitaxial Fe/Cr/Fe(001) trilayers. The lower Fe layer is grown in the shape of a wedge and allows simultaneous preparation of 24 GMR stripe-elements with different lower Fe thicknesses in the range from 13 to 14.5 ML. The layer-by-layer growth mode in combination with the small thickness variation gives rise to: (i) well-controlled roughness changes from stripe to stripe as confirmed by reflection high-energy electron diffraction (RHEED), and (ii) to a varying influence of the underlying Au buffer. The oscillatory roughness variation along the wedge yields an oscillatory GMR behavior as a function of Fe thickness and confirms the previous result that slightly increased interface roughness causes a higher GMR ratio. The proximity of the Au buffer to the GMR trilayer results in an increase of the GMR ratio with increasing Fe thickness. The latter effect is explained by spin-depolarization at the Fe/Au interface and in the bulk of the Au buffer.