Neutron scattering and muon spin relaxation measurements of the noncentrosymmetric antiferromagnet CeCoGe3

Smidman, M., Adroja, D.T., Hillier, A.D., Chapon, L.C., Taylor, J.W., Anand, V.K., Singh, R.P., Lees, M.R., Goremychkin, E.A., Koza, M.M., Krishnamurthy, V.V., Paul, D.M. and Balakrishnan, G. (2013) Neutron scattering and muon spin relaxation measurements of the noncentrosymmetric antiferromagnet CeCoGe3. Physical Review B, 88 (13), 134416. (doi:10.1103/PhysRevB.88.134416).

Abstract

The magnetic states of the noncentrosymmetric pressure-induced superconductor CeCoGe3 have been studied with magnetic susceptibility, muon spin relaxation (?SR), single-crystal neutron diffraction, and inelastic neutron scattering (INS). CeCoGe3 exhibits three magnetic phase transitions at TN1=21,TN2=12, and TN3=8K. The presence of long-range magnetic order below TN1 is revealed by the observation of oscillations of the asymmetry in the ?SR spectra between 13 and 20 K and a sharp increase in the muon depolarization rate. Single-crystal neutron-diffraction measurements reveal magnetic Bragg peaks consistent with propagation vectors of k=(0,0,23) between TN1 and TN2,k=(0,0,58) between TN2 and TN3 and k=(0,0,12) below TN3. An increase in intensity of the (110) reflection between TN1 and TN3 also indicates a ferromagnetic component in these phases. These measurements are consistent with an equal moment two-up two-down magnetic structure below TN3 with a magnetic moment of 0.405(5)?B/Ce. Above TN2, the results are consistent with an equal moment two-up one-down structure with a moment of 0.360(6)?B/Ce. INS studies reveal two crystal-electric-field (CEF) excitations at ?19 and ?27meV. From an analysis with a CEF model, the wave functions of the J=52 multiplet are evaluated along with a prediction for the magnitude and direction of the ground-state magnetic moment. Our model correctly predicts that the moments order along the c axis, but the observed magnetic moment of 0.405(5)?B is reduced compared to the predicted moment of 1.0?B. This is ascribed to hybridization between the localized Ce3+ f electrons and the conduction band. This suggests that CeCoGe3 has a degree of hybridization between that of CeRhGe3 and the noncentrosymmetric superconductor CeRhSi3

This record has no associated files available for download.

Contributors

Download statistics