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We present depth resolved X-ray micro-Laue diffraction experiments on the low temperature domain structure of SrTiO3. At 80K, monochromatic X-ray diffraction shows an elongated out-of-plane unit cell axis within a matrix of in-plane oriented tetragonal unit cells. Full deviatoric strain mappings from white beam diffraction show a dominance of two tetragonal domain orientations (x- and z-axes) over a large area of sample surface. This information sets an upper bound on domain wall widths and offers a method for studying 3D domain structure at low temperatures. [ABSTRACT FROM AUTHOR]

We employed a scanning Hall probe microscope to detect the hopping of individual vortices between pinning sites along grain boundaries in YBa2Cu3O6+δ thin films in the presence of an applied current. Detecting the motion of individual vortices allowed us to probe the current-voltage (I-V) characteristics of the grain boundary with voltage sensitivity below a femtovolt. We find a very sharp onset of dissipation with V∝In with an unprecedented high exponent of n≈290 that shows essentially no dependence on temperature or grain boundary angle. Our data have no straightforward explanation within the existing grain boundary transport models. [ABSTRACT FROM AUTHOR]

The authors have fabricated and characterized GaAs/AlxGa1-xAs two-dimensional electron gas scanning Hall probes for imaging perpendicular magnetic fields at surfaces. The Hall crosses range from 85×85 to 1000×1000 nm2. They study low-frequency noise in these probes, especially random telegraph noise, and show that low-frequency noise can be significantly reduced by optimizing the voltage on a gate over the Hall cross. The authors demonstrate a 100 nm Hall probe with a sensitivity of 0.5 G/[Square_Root]Hz (flux sensitivity of 0.25m[uppercase_phi_synonym]0/[Square_Root]Hz; spin sensitivity of 1.2×104μB/[Square_Root]Hz) at 3 Hz and 9 K. [ABSTRACT FROM AUTHOR]