Evidence for magnetic polarons in EuB6 from small angle neutron scattering

Date

Oct 11, 2017

Time

11:00 AM - 1:00 PM

Speaker

Prof. Dr. A. D. Bianchi

Affiliation

Université de Montréal, Montréal, Canada

Series

MPI-CPfS Festkörperphysikalisches Kolloquium

Language

en

Main Topic

Chemie

Other Topics

Physik, Chemie

Host

Dr. M. Nicklas

Description

One of the outstanding questions in physics is the formation of magnetic moments in metallic systems with a low carrier density. Currently this is only understood in the case of well-localized moments, which are only interacting weakly with the localized moments. However, for the design of materials for spintronic applications, we need to understand the physics in a regime where mobile charge carriers are strongly coupled to the magnetic moments. One way to achieve such a strong interaction is to work with materials with a low carrier density where two competing electronic ground states are close in energy. Switching between these different electronic ground states then leads to large effects in the electronic transport. This scenario is realized in magnetic semi-conductors, transition metal perovskites, transition metal pyrochlores, as well as EuB6, the material studied here. What makes the physics in these colossal magnetoresistance (CMR) materials fascinating is that the CMR effects stem from an electronic phase separation at the nano scale, despite the fact that these materials are chemically homogeneous. “Magnetic polarons”, a new class of quasiparticles, are thought to be responsible for the CMR effects in these materials. Here we present results of a small angle neutron scattering (SANS) study showing definitive evidence of the presence of magnetic polarons in EuB6, making it the first clean model system for studying these new quasiparticles.

Links

• MPI CPfS

Last modified: Oct 11, 2017, 9:55:10 AM