F.E. Atalay

Magnetoimpedance effect in electroplated NiFeRu/Cu wire

Magnetoimpedance (MI) and hysteresis loops were studied in electroplated Ni79.1Fe20.9/Cu, Ni75.64Fe24.26Ru0.10/Cu, Ni79.51Fe20.31Ru0.18/Cu and Ni75.99Fe23.66Ru0.34/Cu wires. Scanning electron micrographs showed that crack-free electroplated wires were obtained with a smooth surface. The average grain size varied between 3 and 10 µm for all samples. It was found that circumferential anisotropy was induced in all samples during the electroplating process. The maximum MI response was 459% at a frequency of 90 kHz, 361% at 110 kHz, 157% at 100 kHz and 114% at 340 kHz for Ni79.1Fe20.9/Cu, Ni75.64Fe24.26Ru0.10/Cu, Ni79.51Fe20.31Ru0.18/Cu and Ni75.99Fe23.66Ru0.34/Cu wires, respectively.

Synthesis of NiO Nanostructures Using Cladosporium Cladosporioides Fungi for Energy Storage Applications

In this work, we produced nickel oxide nanostructures that show high electrochemical capacitive behaviour, using fungus – one of the most common life forms in nature. Cladosporium cladosporioides fungi are particularly attractive biotemplates due to their tubular structures. The nanostructured porous microtubes were prepared by chemical precipitation onto fungi. The morphological properties of the biosynthesized NiO microtubes were studied by transmission electron microscope (TEM). The Brunauer–Emmett–Teller (BET) surface area was found to be 119.72 m2 g−1 with an average pore size distribution of 7.5 nm. A maximum capacitance value of 334 F g−1 was observed at 0.8 A g−1, and a capacitance retention of approximately 95% was obtained after 1000 cycles.

Nanowires of lead-free solder alloy SnCuAg

Ternary Sn88Ag5Cu7, Sn93Ag4Cu3, Sn58Ag18Cu24, Sn78Ag16Cu6, Sn90Ag4Cu6, Sn87Ag4Cu9 alloy nanowires were produced at various values of deposition potential by dc electrodeposition on highly ordered porous anodic alumina oxide (AAO) templates. During the deposition process some parameters, such as ion content, deposition time, pH, and temperature of the solution, were kept constant. The diameter and length of regular Sn93Ag4Cu3 nanowires electrodeposited at - 1V were determined by scanning electron microscopy (SEM) to be approximately 200-250nm and 7-8 µm, respectively. Differential scanning calorimetry (DSC) results indicate that the melting onset temperature of Sn93Ag4Cu3 nanowires is about 204°C.

The Dynamic Effects in Electrodeposited NiFe/Cu Wire with Preliminary Torsion

Ni80Fe20/Cu composite wires were produced under torsion using electrodeposition method. The total length of the magnetic film deposited onto 50 µm Cu wire is 3 cm and the thickness of the magnetic layer is about 10 µm. All samples showed single peak in magnetoimpedance (MI) curves. The magnitude (ΔZ/Z) % are 260%, 235% and 119% for samples produced under 22.4, 44.8, 89.7 rad/m torsion values, respectively at driving frequency of 160 kHz. MI effect magnitude decreases with increasing applied torsion during the electrodeposition process. A linear change in the second harmonics of output voltage from wire ends as a function of applied magnetic field (coil-less fluxgate effect) was observed in all sample. The sensitivity of coil-less output increases with increasing torsion and maximum sensitivity was observed in the sample produced at 89.7 rad/m torsion.

MAGNETIC AND MAGNETOIMPEDANCE PROPERTIES OF NiFe AND CoNiFe FILMS PRODUCED BY ELECTRODEPOSITION TECHNIQUE

Recently, many studies have been carried out to develop ternary CoNiFe (cobalt/nickel/iron) and NiFe alloys due to their capacity of providing an extremely high saturation flux density and a low coercive field strength. In this study, the magnetic properties of NiFe and CoNiFe microtubes were investigated. NiFe and CoNiFe magnetic films were prepared by electrodeposition onto copper wires with a diameter of 50 μm. Coercivity of 61 A/m and a maximum MI response of 186% at a frequency of 900 kHz were obtained for NiFe, which was produced in the pH 1.8 solution.