1202.0221 (F. A. Garcia et al.)

Field dependence of the Eu2+ spin relaxation in EuFe(2-x)CoxAs2    [PDF]

F. A. Garcia, A. Leithe-Jasper, W. Schnelle, M. Nicklas, H. Rosner, J. Sichelschmidt

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 Fe2As2 layers. To address this subject, we have
performed Eu2+ electron spin resonance (ESR), dc-susceptibility measurements
and band structure calculations of EuFe(2-x)CoxAs2 (0.1experiments were carried out at three resonance fields by using three
frequencies (L-, X-, and Q-band). We found that the electronic spin relaxation
is well understood in terms of the exchange coupling among the local spins.
This is shown to be a consequence of the weak coupling between the local and
itinerant subsystems and the high concentration of the ESR probe. The Eu2+ spin
relaxation is field dependent and under direct influence of the magnetic
fluctuations at the Fe(2-x)Cox$As2 layers, presenting the Eu2+ ESR to be
suitable to probe the spin dynamics of the itinerant subsystem.

View original: http://arxiv.org/abs/1202.0221