Evidence for the ion-induced electronic spike on fs and nm scales from transient field measurements

Abstract Measurements of nuclear spin precessions in the transient field (TF) of ferromagnetic gadolinium have provided for the first time evidence for demagnetization effects induced by the energy loss of traversing Mg ions. The primary electronic spike associated with the host electrons is probed in space and time on a nanometer and femtosecond scale by Coulomb-excited 76,80 Se ions recoiling in and near the tracks of preceding 26 Mg ions. The demagnetization that reduces the TF strength is observed via the spin precession of the Se probe ions. The present measurements are sensitive solely to the electronic spike and not to a succeeding lattice spike , as the lattice temperature is substantially lower than the Curie temperature and its build-up occurs significantly later in time than the interaction of the probe ions in the ferromagnet.