Coexistence of glassy antiferromagnetism and giant magnetoresistance (GMR) in Fe/Cr multilayer structures

TL;DR

This study reveals the coexistence of a glassy antiferromagnetic phase and giant magnetoresistance in Fe/Cr multilayers, showing how interlayer exchange coupling influences magnetic behavior at low temperatures.

Contribution

It provides new evidence for a glassy antiferromagnetic phase in Fe/Cr multilayers and links this phase to interlayer exchange coupling effects at low temperatures.

Findings

Presence of a glassy antiferromagnetic phase below 140K

Interlayer exchange coupling influences magnetic behavior at low T

GMR effect remains robust at room temperature despite minor IEC influence

Abstract

Using temperature-dependent magnetoresistance and magnetization measurements on Fe/Cr multilayers that exhibit pronounced giant magnetoresistance (GMR), we have found evidence for the presence of a glassy antiferromagnetic (GAF) phase. This phase reflects the influence of interlayer exchange coupling (IEC) at low temperature (T < 140K) and is characterized by a field-independent glassy transition temperature, Tg, together with irreversible behavior having logarithmic time dependence below a "de Almeida and Thouless" (AT) critical field line. At room temperature, where the GMR effect is still robust, IEC plays only a minor role, and it is the random potential variations acting on the magnetic domains that are responsible for the antiparallel interlayer domain alignment.