Hyperfine Fields in an Ag/Fe Multilayer Film Investigated with 8Li beta-Detected Nuclear Magnetic Resonance

TL;DR

This study uses beta-detected NMR to measure how magnetic fields induced by Fe decay in a nonmagnetic Ag layer within a multilayer film, revealing a near-inverse-square decay pattern.

Contribution

It provides the first detailed measurement of the spatial decay of hyperfine fields in Ag induced by Fe in a multilayer structure using beta-NMR.

Findings

Hyperfine fields in Ag decay approximately as a power law with exponent -1.93.

Induced hyperfine field at the interface is about 0.23 T.

Resonance lineshape broadening indicates large induced magnetic fields.

Abstract

Low energy $\beta$-detected nuclear magnetic resonance ($\beta$-NMR) was used to investigate the spatial dependence of the hyperfine magnetic fields induced by Fe in the nonmagnetic Ag of an Au(40 \AA)/Ag(200 \AA)/Fe(140 \AA) (001) magnetic multilayer (MML) grown on GaAs. The resonance lineshape in the Ag layer shows dramatic broadening compared to intrinsic Ag. This broadening is attributed to large induced magnetic fields in this layer by the magnetic Fe layer. We find that the induced hyperfine field in the Ag follows a power law decay away from the Ag/Fe interface with power $-1.93(8)$, and a field extrapolated to $0.23(5)$ T at the interface.