Ames Laboratory; Physics and Astronomy
Ames Laboratory, Physics and Astronomy
Physical Review B
Filled skutterudite compound EuFe4As12 shows the highest magnetic ordering temperature of TC=154K among Eu-based skutterudite compounds, but its magnetic ground state has not been determined yet. Here, we performed 153Eu nuclear magnetic resonance (NMR) and 75As nuclear quadrupole resonance (NQR) measurements on EuFe4As12 to reveal its magnetic ground state as well as the physical properties from a microscopic point of view. From the temperature and magnetic field dependence of 153Eu NMR spectrum in the magnetically ordered state, we found that the Eu ions are in Eu2+ state with a nearly 7 μB corresponding to S=7/2 spins. Combined with the magnetization measurements, which show the reduced saturation moments of 4.5 μB/f.u., we determined the ground magnetic structure in EuFe4As12 to be ferrimagnetic where the Eu2+ 4f and the Fe3d ordered moments are ferromagnetically aligned in each sublattice but the moments between the sublattices are antiferromagnetically aligned. We also found the local distortion at the Eu site from the cubic symmetry in the magnetically ordered state. The relationship between the rattling motion of Eu atoms and the local symmetry of the Eu ions is discussed. From the 75As NQR nuclear spin-lattice relaxation time measurements as well as 153Eu NMR measurements, we found that the 4f electrons of the Eu ions are well described by the local moment picture in both the magnetic and paramagnetic metallic states.
DOE Contract Number(s)
AC02-07CH11358; 23340092; 19K03735
Iowa State University Digital Repository, Ames IA (United States)