Muon spin rotation and neutron scattering study of the noncentrosymmetric tetragonal compound CeAuAl3

Adroja, D.T. ; De la Fuente, C. (Universidad de Zaragoza) ; Fraile, A. ; Hillier, A.D. ; Daoud-Aladine, A. ; Kockelmann, W. ; Taylor, J.W. ; Koza, M.M. ; Burzurí, E. ; Luis, F. (Universidad de Zaragoza) ; Arnaudas, J.I. (Universidad de Zaragoza) ; Del Moral, A.

Resumen: We have investigated the noncentrosymmetric tetragonal heavy fermion compound CeAuAl3 using muon spin rotation (µSR), neutron diffraction (ND), and inelastic neutron scattering (INS) measurements. We have also revisited the magnetic, transport, and thermal properties. The magnetic susceptibility reveals an antiferromagnetic transition at 1.1 K with, possibly, another magnetic transition near 0.18 K. The heat capacity shows a sharp ¿-type anomaly at 1.1 K in zero field, which broadens and moves to a higher temperature in an applied magnetic field. Our zero-field µSR and ND measurements confirm the existence of a long-range magnetic ground state below 1.2 K. Further, the ND study reveals an incommensurate magnetic order with a magnetic propagation vector k=(0, 0, 0.52(1)) and a spiral structure of Ce moments coupled ferromagnetically within the ab plane. Our INS study reveals the presence of two well-defined crystal electric field (CEF) excitations at 5.1 and 24.6 meV in the paramagnetic phase of CeAuAl3 that can be explained on the basis of the CEF theory and the Kramer''s theorem for a Ce ion having a 4f1 electronic state. Furthermore, low energy quasielastic excitations show a Gaussian line shape below 30 K compared to a Lorentzian line shape above 30 K, indicating a slowdown of spin fluctuations below 30 K. We have estimated a Kondo temperature of TK=3.5K from the quasielastic linewidth, which is in good agreement with that estimated from the heat capacity. This study also indicates the absence of any CEF-phonon coupling unlike that observed in isostructural CeCuAl3 The CEF parameters, energy level scheme, and their wave functions obtained from the analysis of INS data explain satisfactorily the single crystal susceptibility in the presence of two-ion anisotropic exchange interaction in CeAuAl3.

Idioma: Inglés

DOI: 10.1103/PhysRevB.91.134425

Año: 2015

Publicado en: Physical Review B 91, 13 (2015), 134425 [12 p.]
ISSN: 1098-0121

Factor impacto JCR: 3.718 (2015)

Categ. JCR: PHYSICS, CONDENSED MATTER rank: 16 / 67 = 0.239 (2015) - Q1 - T1

Factor impacto SCIMAGO: 2.377 - Electronic, Optical and Magnetic Materials (Q1) - Condensed Matter Physics (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E81
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2009-10040
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2012-30763

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)