Magnetic state of Nb(1-7nm)/Cu$_{30}$Ni$_{70}$(6nm) superlattices revealed by Polarized Neutron Reflectometry and SQUID magnetometry

TL;DR

This study investigates the magnetic properties of Nb/CuNi superlattices using polarized neutron reflectometry and SQUID magnetometry, revealing antiferromagnetic coupling primarily in the out-of-plane magnetic moment component.

Contribution

It provides new insights into the magnetic coupling behavior in Nb/CuNi superlattices, highlighting the anisotropic nature of antiferromagnetic interactions.

Findings

Magnetic moment increases linearly with applied field up to saturation.

Antiferromagnetic coupling detected indirectly via magnetization measurements.

PNR did not observe in-plane AF coupling, suggesting out-of-plane anisotropy.

Abstract

We report results of a magnetic characterization of [Cu$_{30}$Ni$_{70}$(6nm)]$_{20}$ (x=1-7nm) superlattices using Polarized Neutron Reflectometry (PNR) and SQUID magnetometry. The study has shown that the magnetic moment of the structures growths almost linearly from H = 0 to H$_{sat}$ = 1.3kOe which is an indirect evidence of antiferromagnetic (AF) coupling of the magnetic moments in neighbouring layers. PNR, however, did not detect any in-plane AF coupling. Taking into account the out-of-plane easy axis of the Cu$_{30}$Ni$_{70}$ layers, this may mean that only the out-of-plane component of the magnetic moments are AF coupled.