Direct observation of rare-earth-host interactions in Er:Y2SiO5

We report the direct observation of Er-Y and Er-Si interactions in Er:Y2SiO5 by spin-echo measurements. Modulations in the spin-echo decay of Er3+ ions are due to magnetic interactions between the rare earth and the host nuclear spins. The closest yttrium ions were found to be out of resonance compared to the yttrium ions farther away from the rare earth. This strong frozen core effect around the Er3+ ions suggests that the influence of Y3+ ions on the decoherence processes of erbium is weaker than what can be deduced from the yttrium in the bulk.