MUSR Insights into Spin Dynamics within Frustrated Inter-metallic YbCuAs2

Synopsis

This study presents an in-depth investigation of intermetallic YbCuAs₂, a Kondo lattice system, using muon spin relaxation/rotation techniques, comparing the observed local magnetic response with reported macroscopic transport and thermodynamic phenomena. Long-range magnetic ordering is confirmed below 3.7K, contrary to neutron diffraction measurements. Spontaneous muon spin precession frequencies below the phase transition yield the local magnetic field and evolution of the sublattice magnetization. Above the ordering temperature, four regimes in temperature are observed using μSR, which correlate directly with features in specific heat and resistivity measurements. Density functional theory calculations suggest three potential muon sites, while point charge crystal electric field calculations yield the electronic energy levels of the  ion in its crystalline environment. Additionally, calculations of the spin-lattice relaxation rate and nuclear dipolar field provide a more comprehensive picture of the electronic and nuclear contributions to the μSR signal.