Tuning the bottleneck effect in Ag metallic host doped with magnetic Gd and non-magnetic Sb ions

摘要

The Ag metallic host doped with Gd and Sb is an excellent model system to study the bottleneck effect associated to the conduction-electron (c-e) spin-flip scattering mechanism. Electron spin resonance of Gd3+ in both, Ag-(Gd doped)- and Ag-(Gd and Sb doped)-systems, reveal the presence of bottleneck which can be tuned by the amount of Gd and Sb impurities. The increase of the Gd concentration leads to a c-e spin-flip relaxation rate to the magnetic Gd3+ ions larger than that to the lattice, favoring the bottleneck regime. Whereas the effect of the non-magnetic impurities (Sb ions) is to increase, via spin-orbit scattering, the spin-flip relaxation rate of the c-e to the lattice, weakening the bottleneck regime.