Depth resolved properties of nanoscopic heterostructures using ß-NMR

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When materials are combined, not through formation of a compound, but instead into a heterostructure (in the simplest instance, a thin film of one material on a substrate of another) the resulting properties may differ substantially from those of each of the pure bulk starting materials. Such "metamaterials" have important applications in electronics and sensors, and newly developed metamaterials can have unprecedented properties which may form the basis of entirely new technologies, such as quantum computers or spintronics. In a similar way, the properties of materials differ at a free surface, for example, in surface reconstruction, the crystal structure of atoms at the surface is different from that of a simple truncation of the bulk. Such effects can (and generally do) propagate below the surface. Thus, the properties of metamaterials and crystals near a free surface are depth dependent. Remarkably little is known about such phenomena, mainly because very few depth-resolved techniques are available. This proposal aims to use the technique of low energy beta detected nuclear magnetic resonance at TRIUMF, Canada's National Lab for Particle and Nuclear Physics, as a new depth-resolved (at the nanometer scale, i.e. one billionth of a meter) experimental probe of solid materials, addressing fundamental and practical questions in, for example, magnetism and superconductivity in nanoscopically structured metamaterials. The diffusive motion of ions in solids is another practically important property (for instance in solid state electrochemical batteries) that is modified (and depth-dependent) in the vicinity of an interface or free surface. The proposal also aims to study diffusion of the isolated probe ions in this context.