Advanced calibration kit for scanning microwave microscope: Design, fabrication, and measurement.

We present in this paper a new design of a capacitive calibration kit for scanning microwave microscopy (SMM). As demonstrated by finite element modelings, the produced devices are highly independent of material parameters due to their lateral configuration. The fabrication of these gold-based structures is realized by using well established clean-room techniques. SMM measurements are performed under different conditions, and all capacitive structures exhibit a strong contrast with respect to the non-capacitive background. The obtained experimental data are employed to calibrate the used SMM tips and to extract the capacitance of produced devices following a method based on the short-open-load calibration algorithm for one-port vector network analyzers. The comparison of experimental capacitance and nominal values provided by our models proves the applicability of the used calibration approach for a wide frequency range.

Imaging Stray Magnetic Field of Individual Ferromagnetic Nanotubes.

We use a scanning nanometer-scale superconducting quantum interference device to map the stray magnetic field produced by individual ferromagnetic nanotubes (FNTs) as a function of applied magnetic field. The images are taken as each FNT is led through magnetic reversal and are compared with micromagnetic simulations, which correspond to specific magnetization configurations. In magnetic fields applied perpendicular to the FNT long axis, their magnetization appears to reverse through vortex states, that is, configurations with vortex end domains or in the case of a sufficiently short FNT with a single global vortex. Geometrical imperfections in the samples and the resulting distortion of idealized magnetization configurations influence the measured stray-field patterns.

Architectonics of the hair of sled dogs of Chukotka.

Architectonics of guard hairs from dogs of recent breeds, mongrel sled dogs, and fossil dogs from ancient settlements of Chukotka have been investigated using scanning electron microscopy. Distinct features of hair structure important for adaptation, including the adaptation to harness in sled dogs, were identified. Hairs of Chukchi sled dogs were most similar to those of the fossil dogs.

Scanning superconducting quantum interference device on a tip for magnetic imaging of nanoscale phenomena.

We describe a new type of scanning probe microscope based on a superconducting quantum interference device (SQUID) that resides on the apex of a sharp tip. The SQUID-on-tip is glued to a quartz tuning fork which allows scanning at a tip-sample separation of a few nm. The magnetic flux sensitivity of the SQUID is 1.8 µΦ(0)/√Hz and the spatial resolution is about 200 nm, which can be further improved. This combination of high sensitivity, spatial resolution, bandwidth, and the very close proximity to the sample provides a powerful tool for study of dynamic magnetic phenomena on the nanoscale. The potential of the SQUID-on-tip microscope is demonstrated by imaging of the vortex lattice and of the local ac magnetic response in superconductors.