H. Saadaoui

Local magnetic properties of a monolayer of Mn12 single molecule magnets.

The magnetic properties of a monolayer of Mn12 single molecule magnets grafted onto a silicon (Si) substrate have been investigated using depth-controlled beta-detected nuclear magnetic resonance. A low-energy beam of spin-polarized radioactive 8Li was used to probe the local static magnetic field distribution near the Mn12 monolayer in the Si substrate. The resonance line width varies strongly as a function of implantation depth as a result of the magnetic dipolar fields generated by the Mn12 electronic magnetic moments. The temperature dependence of the line width indicates that the magnetic properties of the Mn12 moments in this low-dimensional configuration differ from bulk Mn12.

Nature of weak magnetism in SrTiO3/LaAlO3 multilayers.

We report the observation of weak magnetism in superlattices of LaAlO(3)/SrTiO(3) using β-detected nuclear magnetic resonance. The spin lattice relaxation rate of ^{8}Li in superlattices with a spacer layers of 8 and 6 unit cells of LaAlO(3) exhibits a strong peak near ~35 K, whereas no such peak is observed in a superlattice with spacer layer thickness of 3 unit cells. We attribute the observed temperature dependence to slowing down of weakly coupled electronic moments at the LaAlO(3)/SrTiO(3) interface. These results show that the magnetism at the interface depends strongly on the thickness of the spacer layer, and that a minimal thickness of ~4-6 unit cells is required for the appearance of magnetism. A simple model is used to determine that the observed relaxation is due to small fluctuating moments (~0.002μ(B)) in the two samples with a larger LaAlO(3) spacer thickness.

Near-Surface Structural Phase Transition of SrTiO~3 Studied with Zero-Field beta-Detected Nuclear Spin Relaxation and Resonance

We demonstrate that zero-field beta-detected nuclear quadrupole resonance and spin relaxation of low energy (8)Li can be used as a sensitive local probe of structural phase transitions near a surface. We find that the transition near the surface of a SrTiO(3) single crystal occurs at T(c) approximately 150K, i.e., approximately 45K higher than T(c)bulk, and that the tetragonal domains formed below T(c) are randomly oriented.

Magnetic-field effects on the size of vortices below the surface of NbSe2 detected using low energy beta-NMR.

A low energy radioactive beam of polarized

Search for broken time-reversal symmetry near the surface of superconducting YBa2Cu3O7-δ films using β-detected nuclear magnetic resonance

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Mott transition in granular aluminum

Li has been used to observe the vortex lattice near the surface of superconducting NbSe

Absence of spontaneous magnetism associated with a possible time-reversal symmetry breaking state beneath the surface of (110)-oriented YBa2Cu3O7−δsuperconducting films

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Depth dependence of the structural phase transition of SrTiO3studied withβ-NMR and grazing incidence x-ray diffraction

. The inhomogeneous magnetic field distribution associated with the vortex lattice was measured using depth-resolved

Vortex lattice disorder inYBa2Cu3O7−δprobed usingβ-NMR

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Low-energy muons at PSI: examples of investigations of superconducting properties in near-surface regions and heterostuctures

-detected NMR. Below