Magnetic resonance and magnetic anisotropy oscillations in Co/Cu (111) superlattices

Abstract

Magnetic resonance was studied in magnetic fields parallel or perpendicular to the film plane in magnetron-sputtered [Co(8 Å)/Cu(dCu)(111)]20 multilayers. Oscillations of the magnetic anisotropy KA and the width ΔHres of the resonance line as a function of the thickness of the copper interlayers were found in the interval dCu=7–19 Å. Extrema of KA and ΔHres were observed at dCu=nd(111), where n is an integer or half-integer, and d(111)=2.087 Å—the distance between the (111) planes in Cu. In addition, the distances between the neighboring maxima or minima were 1, 1.5, and 2d(111). The KA and ΔHres oscillations occurred synchronously with oscillations of the resistivity at saturation (in the field H=15 kOe) and oscillations of the magnetoresistance. An interlayer antiferromagnetic exhange interaction was found in the ranges dCu=8–11 Å and dCu⩾18 Å. The effects observed were due to nonmonotonic variation of the interlayer interface roughness with increasing dCu.

Oscillations of the ferromagnetic resonance linewidth and magnetic phases in Co/Ru superlattices

“…8 reveals, the inhomogeneity of the IEC strength scales with the coupling between Co layers on the Ru thickness, leading to oscillations of the linewidth as a function of t Ru . Oscillations and broadening of the FMR linewidth due to inhomogeneities were also reported in Co/Cu multilayers, 15 Co/Cu superlattices, 16 and NiFe/Ru/ NiFe trilayers. 17…”

“…This effect scales with the IEC and thus, oscillations of the linewidth as a function of the spacer thickness may be understood as oscillations of the IEC. 14,16,17 Here, the FMR measurements in Co/Ru superlattices show that the dependence of the FMR linewidth of the main mode on the thickness of the Ru spacer reflects the oscillations of the IEC.…”