Speaker
Kirill Nemkovskiy
Description
We present an inelastic neutron scattering study of the influence of isoelectronic Tm substitution on the low-energy structure and temperature dependence of the dynamical magnetic response in (Yb,Tm)B12 solid solutions. Substantial changes have been observed in the spectral structure and temperature evolution of the Yb contribution to the inelastic response for a rather low content of magnetic Tm ions. The spin-exciton-like resonance mode near 15 meV is steeply suppressed at the lowest measured Tm concentration (x = 0.08). The spin gap is replaced by a pseudogap at concentrations lower than 0.15. These results point to a specific effect of impurities carrying a magnetic moment (Tm, as compared to Lu or Zr) in a Kondo insulator, which is thought to reflect the “under-compensation” of Yb magnetic moments, originally screened in pure YbB12. A parallel is made with the strong effect of Tm substitution on the temperature dependence of the Seebeck coefficient in (Yb,Tm)B12.
Primary author
Co-authors
Dr
Alexandre Ivanov
(Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9, France)
Prof.
Jean-Michel Mignot
(Laboratoire Léon Brillouin, CEA-CNRS, CEA/Saclay, 91191 Gif sur Yvette, France)
Dr
Natalya Shitsevalova
(I. N. Frantsevich Institute for Problems of Materials Science, 03142 Kiev, Ukraine)
Prof.
Pavel Alekseev
(National Research Centre “Kurchatov Institute”, 123182 Moscow, Russia; National Research Nuclear University “MEPhI”, 115409, Moscow, Russia)
Dr
Stephane Rols
(Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9, France)
Dr
Volodymyr Filipov
(I. N. Frantsevich Institute for Problems of Materials Science, 03142 Kiev, Ukraine)
