The layered compound EuFe2As2 is an interesting model system to investigate the effects of well defined local Eu2+ 4f states on the itinerant electronic and magnetic properties of the FeAs layers. To address this subject, we investigated the series EuFe2-xCoxAs2 (0.1 <= x <=0.75) by electron spin resonance (ESR) of Eu2+ to probe the spin dynamics of the itinerant subsystem. We relate the results to dc-susceptibility measurements and band structure calculations. As a consequence of the weak coupling between the local and itinerant subsystems we found that the spin relaxation is well understood in terms of the exchange coupling among the local Eu2+ spins. A pronounced field dependence of the Eu2+ spin relaxation demonstrates the direct influence of magnetic fluctuations at the Fe2-xCoxAs2 layers.
@article{arxiv.1202.0221,
title = {Field dependence of the Eu2+ spin relaxation in EuFe(2-x)CoxAs2},
author = {F. A. Garcia and A. Leithe-Jasper and W. Schnelle and M. Nicklas and H. Rosner and J. Sichelschmidt},
journal= {arXiv preprint arXiv:1202.0221},
year = {2015}
}