Kondo Screening and Magnetic Ordering in Frustrated UNi4B

TL;DR

This paper investigates the coexistence of magnetic and nonmagnetic uranium sites in UNi4B, attributing it to the interplay of Kondo screening and magnetic frustration, revealing complex low-temperature magnetic behavior.

Contribution

It introduces a model explaining the coexistence of magnetic and nonmagnetic U sites due to frustration and Kondo effects in UNi4B, a novel insight into its magnetic properties.

Findings

1/3 of U sites are nonmagnetic due to Kondo effect.

The magnetic order results from competition between frustration and 5f moment instability.

The model explains the unique antiferromagnetic arrangement in UNi4B.

Abstract

UNi4B exhibits unusual properties and, in particular, a unique antiferromagnetic arrangement involving only 2/3 of the U sites. Based on the low temperature behavior of this compound, we propose that the remaining 1/3 U sites are nonmagnetic due to the Kondo effect. We derive a model in which the coexistence of magnetic and nonmagnetic U sites is the consequence of the competition between frustration of the crystallographic structure and instability of the 5f moments.