Longitudinal and perpendicular exchange bias in FeMn/(FeNi/FeMn)n multilayers

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Date
2003-05-15
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Publisher
American Institute of Physics
Abstract
Exchange bias in ferromagnetic (FM)/antiferromagnetic (AF) bilayers is usually investigated in the longitudinal configuration with the exchange coupling established in the film plane. In this work, we report on the perpendicular exchange bias in FeMn(8 nm)/[FeNi(2 nm)/FeMn(8 nm)]n multilayers induced by perpendicular field cooling. The thin FeNi layers give rise to large values of the exchange field and coercivity, and n=15 allows a sufficiently large magnetization for the measurements. Even though the soft FeNi layers have an intrinsic in-plane anisotropy, perpendicular exchange bias has been observed after cooling in a perpendicular external field. The exchange field in the perpendicular configuration is about 0.85 that of the longitudinal case. In both the longitudinal and perpendicular configurations, the exchange field decreases quasilinearly with temperature. The squareness of perpendicular hysteresis loops decreases with increasing temperature.
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Keywords
perpendicular magnetic anisotropy, nickel alloys, manganese alloys, magnetic multilayers, magnetic hysteresis, iron alloys, ferromagnetic materials, antiferromagnetic materials, exchange interactions (electron), longitudinal exchange bias, ferromagnetic/antiferromagnetic bilayers, perpendicular field cooling, coercivity, intrinsic in-plane anisotropy, perpendicular hysteresis loops, FeMn-FeNi-FeMn
Citation
Journal of Applied Physics 15 May 2003, vol.93, no.10, pp. 6841-3