Muon Spin Rotation Analysis of the Internal Magnetic Field of Heavy Fermion System Uranium Beryllium-13

TL;DR

This study uses muon spin spectroscopy to analyze the internal magnetic field distribution in uranium beryllium-13, revealing magnetic site characteristics crucial for understanding its heavy fermion behavior.

Contribution

It introduces a detailed muon spin analysis method for identifying magnetic sites in heavy fermion systems, applicable to other compounds and relevant for quantum technology.

Findings

Two precession frequencies observed at low temperatures

Muon stopping sites traced to geometric centers of the lattice edges

Identification of strong and weak magnetic sites

Abstract

Uranium beryllium-13 is a heavy fermion system whose anomalous behavior may be explained by its poorly understood internal magnetic structure. Here, uranium beryllium-13's magnetic distribution is probed via muon spin spectroscopy ($\mu$SR)-a process where positive muons localize at magnetically unique sites in the crystal lattice and precess at characteristic Larmor frequencies, providing measurements of the internal field. Muon spin experiments using the transverse-field technique conducted at varying temperatures and external magnetic field strengths are analyzed via statistical methods on ROOT. Two precession frequencies are observed at low temperatures with an amplitude ratio in the Fourier transform of 2:1, enabling muon stopping sites to be traced at the geometric centers of the edges of the crystal lattice. Characteristic strong and weak magnetic sites are deduced, additionally verified by mathematical relationships. Results can readily be applied to other heavy fermion systems, and recent identification of quantum critical points in a host of heavy fermion compounds show a promising future for the application of these systems in quantum technology. Note that this paper is an analysis of data, and all experiments mentioned here are conducted by a third party.