Quantum States of Neutrons in Magnetic Thin Films

TL;DR

This study investigates how polarized neutrons interact with magnetic thin films and multilayers, revealing how critical reflection edges depend on magnetization orientation and multilayer configuration.

Contribution

It provides a unified spinor-based explanation for neutron reflection behavior in both single films and multilayers, including the interpretation of ferromagnetic and antiferromagnetic states.

Findings

Critical edges are fixed in single films with intensity depending on polarization angle.

In multilayers, critical edges for spin states move closer as magnetization angles change.

The same spinor method explains behaviors in both single and multilayer structures.

Abstract

We have studied experimentally and theoretically the interaction of polarized neutrons with magnetic thin films and magnetic multilayers. In particular, we have analyzed the behavior of the critical edges for total external reflection in both cases. For a single film we have observed experimentally and theoretically a simple behavior: the critical edges remain fixed and the intensity varies according to the angle between the polarization axis and the magnetization vector inside the film. For the multilayer case we find that the critical edges for spin up and spin down polarized neutrons move towards each other as a function of the angle between the magnetization vectors in adjacent ferromagnetic films. Although the results for multilayers and single thick layers appear to be different, in fact the same spinor method explains both results. An interpretation of the critical edges behavior for the multilyers as a superposition of ferromagnetic and antifferomagnetic states is given.