Anomalous spin relaxation and quantum criticality in Mn1-xFexSi solid solutions1)
S. V. Demishev+*, A. N. Samarin+*, V. V. Glushkov+*, M. I. Gilmanov+*, I. I. Lobanova+*, N. A. Samarin+, A. V. Semeno+, N. E. Sluchanko+, N. M. Chubova×, V. A. Dyadkin×, S. V. Grigoriev×
+Prokhorov General Physics Institute of the RAS, 119991 Moscow, Russia
*Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
×Konstantinov St.Petersburg Nuclear Physics Institute, 188300 Gatchina, Russia
Abstract
We report results of the high frequency (60 GHz) electron spin
resonance (ESR)
study of the quantum critical metallic system Mn1- xFexSi.
The ESR is
observed for the first time in the concentration range 0 < x < 0.24
at
temperatures up to 50 K. The application of the original experimental
technique allowed carrying out line shape analysis and finding full set
of
spectroscopic parameters, including oscillating magnetization, line
width and
g factor. The strongest effect of iron doping consists in influence
on the
ESR line width and spin relaxation is marked by both violation of the
classical Korringa-type relaxation and scaling behavior.
Additionally, the
non-Fermi-liquid effects in the temperature dependence of the ESR
line width,
which may be quantitatively described in the theory of Wölfle and
Abrahams,
are observed at quantum critical points and
.