| AVS 62nd International Symposium & Exhibition | |
| Scanning Probe Microscopy Focus Topic | Wednesday Sessions |
| Session SP+2D+AS+NS+SS-WeA |
| Session: | Probing Electronic and Transport Properties |
| Presenter: | William Paul, IBM Research - Almaden |
| Authors: | W. Paul, IBM Research - Almaden S. Baumann, IBM Research - Almaden K. Yang, Chinese Academy of Sciences N. Romming, University of Hamburg, Germany T. Choi, IBM Research - Almaden C.P. Lutz, IBM Research - Almaden A. Heinrich, IBM Research - Almaden |
| Correspondent: | Click to Email |
A single atomic spin constitutes the ultimate limit to the miniaturization of magnetic bits. Can the state of such a spin be made stable against the quantum mechanical tunneling of magnetization? The energy relaxation time, T1, of single spins on surfaces can be measured by spin-polarized pump-probe STM [1]. To date, the relaxation times reported for Fe-Cu dimers on Cu2N insulating films have been of the order ~100 ns [1]. A three-order-of-magnitude enhancement of lifetime, to ~200 µs, was recently demonstrated for Co on a single-monolayer of MgO [2]. This was accomplished by choosing a less conductive decoupling layer to electronically separate the atom from a metal substrate, along with the careful design of the symmetry of orbital states. Here, we report on the tailoring of the T1 lifetime of single Fe atoms on single- and multi- layer MgO films grown on Ag(001). We focus on the characterization of intrinsic lifetimes for the atom-substrate system which are independent of the STM tip used to probe them, that is, without influence of the nearby STM tip which can be a strong source of electronic de-excitation. We also report on new advances in pump-probe techniques which were necessary to carry out these measurements. These advances extend lifetime detection to the femto-ampere and many-millisecond regimes demanded by the Fe on MgO system.
[1] Loth et al., Science 329, 1628 (2010)
[2] Rau et al., Science 344, 988 (2014).