Influence of a magnetic field on the antiferromagnetic order in UPt_3

TL;DR

This study used neutron diffraction to examine how magnetic fields affect antiferromagnetic order in UPt_3, revealing that fields up to 3.2 Tesla do not alter the magnetic domains or moments, challenging existing theories.

Contribution

It provides experimental evidence that magnetic fields up to 3.2 Tesla do not influence antiferromagnetic order in UPt_3, impacting theories of its superconducting phase diagram.

Findings

Magnetic field up to 3.2 Tesla has no effect on antiferromagnetic order.

Magnetic domains are unaffected by in-plane magnetic fields.

Results challenge current models linking magnetic order to superconductivity.

Abstract

A neutron diffraction experiment was performed to investigate the effect of a magnetic field on the antiferromagnetic order in the heavy fermion superconductor UPt_3. Our results show that a field in the basal plane of up to 3.2 Tesla, higher than H_c2(0), has no effect: it can neither select a domain nor rotate the moment. This has a direct impact on current theories for the superconducting phase diagram based on a coupling to the magnetic order.