A. E. Ozmetin

Flux pinning with a magnetic nanorod array

We report measurements of the phase diagram and critical current of a PbBi superconducting film with an embedded square array of Ni nanorods. Strong hysteresis of the superconducting properties and an increase in the critical current which varies from several times to several orders of magnitude depending on the magnetic field and temperature is found.

Strong increase in critical field and current in magnet-superconductor hybrids

Superconducting properties of 60 nm thick lead bismuth (Pb82Bi18) films in a spatially varying magnetic field created by a hybrid structure of soft magnetic (25 μm wide iron) and nonmagnetic (250 μm wide brass) layers perpendicular to the superconducting film surface are reported. The applied homogeneous external magnetic field is redistributed in the superconducting film due to the high magnetic permeability of iron. This results in alternating parallel stripes of regions of low and high magnetic field. Thus the values of second critical field HC2 and critical current density are also much higher for current parallel to the magnetic stripes than in a control superconducting film without any magnetic field modulation. For the current perpendicular to the magnetic stripes, the superconductor behaves like an inhomogeneous resistor with regions of low and higher TC in series. Thus, the critical current IC for the perpendicular case is much less than either the control film or the case for current parallel to...

HYSTERESIS OF THE PHASE DIAGRAM IN THE FERROMAGNET-SUPERCONDUCTOR HYBRIDS

After the 100th year anniversary of the discovery of superconductivity, the field continues to develop in several directions; including ferromagnet-superconductor hybrids.1-5 Magnetic and superconducting states are perhaps the most extreme example of mutually exclusive states. However, when combined at the nanoscale, they show new exciting properties and enhanced superconductivity. Here we report the measurements and simulation of the phase diagram of a thin superconducting film with an array of magnetic nanorods (MNR) embedded in the film. Results of the experimental measurements of the phase diagram of a PbBi superconducting film with embedded arrays of Ni nanorods are reported and compared with the simulated phase diagrams.

Experimental Characterization of Micromachined Electromagnetic Probes using Scanning Hall Probe Microscopy

We present the experimental characterization of micromachined electromagnetic probe using scanning Hall probe microscopy. The tested electromagnetic probe consists of a protruding sharp Permalloy needle embedded into a three-dimensional gold conducting coil, which is fabricated with a simple and straightforward micromachining process. By using a scanning Hall probe microscope, a comprehensive high-spatial resolution characterization of the probe performance (e.g. peak magnetic intensity and spatial field distribution) is achieved for the first time.