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In this study, Fe40Ni38Mo4B18 (2826MB) amorphous ferromagnetic ribbons were used as a magnetoelastic sensor. The variation in resonance frequency and quality (Q) factor values of samples with a 30 mm length and different widths is investigated as a function of a magnetic field. It is observed that as the sample width increases, the change in resonance frequency and the Q factor both decrease. The parameter Q×amplitude=M is defined to understand the effect of a ribbon width on the resonance curve. According to this parameter, samples with 1 and 2 mm widths are found to have a better magnetoelastic effect. [ABSTRACT FROM AUTHOR]

The ΔE effect was studied using Fe77B16Si5Cr2 amorphous ribbon, and asymmetry in the ΔE curves was created using micro magnets placed on the surface of the ribbon. Asymmetry was also observed in the vibration amplitude versus the magnetic field, and magnetization loops of amorphous ribbons with micro magnets were observed. The results show that the asymmetries in the ΔE curves and magnetisation loops are in agreement with each other. A linear change in vibration amplitude as a function of the applied magnetic field in the ±100 A/m region was observed, which is important for sensor applications. [ABSTRACT FROM AUTHOR]

In this study, the effect of Fe, Mn and Cr substitution for Co on the crystallization kinetics of amorphous Co75-xMxSi15B10 (M = Fe, Mn and Cr; x = 0 and 5) alloys were investigated. The broad diffraction peaks in the X-ray diffraction patterns for as-quenched ribbons indicated that all of the samples exhibit an amorphous structure. The activation energies of the alloys were calculated from differential thermal analysis data using the Kissinger, Ozawa and Augis-Bennett models. The increased activation energy for Fe, Mn and Cr doped samples indicated that the thermal stability and the crystallization kinetics were improved in the doped samples. The value of the Avrami exponent indicated that the crystallization is typical diffusion controlled three-dimensional growth for all of the samples. [ABSTRACT FROM AUTHOR]

In this study, free standing NiO nanostructures for supercapacitors were obtained by means of chemically depositing of nickel oxide on Ni foam and then they were annealed at various temperatures. The morphological properties of densely covered Ni foams were studied by scanning electron microscopy. Supercapacitor characteristics, such as charging/discharging and impedance characteristics, were also examined. [ABSTRACT FROM AUTHOR]

In this work, NiFe nanowires were grown in highly ordered porous anodic alumina oxide templates by dc electrodeposition at a pH value of 2.6. Scanning electron microscopy showed that wires have diameters of about 250-310 nm and length 25-30 μm. The energy dispersive X-ray analysis showed that the composition of the nanowires is Ni6535. Electrical contacts were made on both sides of the nanowire array and their magnetoimpedance properties were investigated. All the magnetoimpedance curves showed single peak behavior due to the high shape anisotropy. The maximum magnetoimpedance change at the 79 MHz driving current frequency was ≈ 1.45%. [ABSTRACT FROM AUTHOR]

In this study, magnetic properties of Pr0.67Ca0.33MnO3 compound were investigated in detail. The magnetization versus temperature (M-T) curve showed that this material undergoes a charge order transition at 200 K. A more pronounced FM phase appeared below 56 K. At T = 5 K, a field induced sharp step like magnetisation transition associated with phase separation was observed. However, after application of 7 T magnetic field at 5 K, the magnetic behaviour of sample was changed completely and full FM behaviour was observed. The more interesting is that the sample remains in the FM state and does not retrieve the initial magnetic state until warmed up to charge order transition temperature. Large negative magnetic entropy change (-26.18 J/(kg K) at 38 K and 5 T) was attributed to step like magnetisation transition. [ABSTRACT FROM AUTHOR]

La0.67Ca0.33MnO3 perovskite-type manganite was synthesized by high-energy ball milling raw oxides of La2O3 (purity 99.9%), CaCO3 (purity > 99%), and MnO (purity > 99%). The ratio of ball and powder weight was 10:1 and the rotating speed was set to 500 rpm. X-ray analysis indicated that La0.67Ca0.33MnO3 single phase was formed completely when milling time is up to 4 h. The peak intensity of perovskite structure decreased and a hump-like peak appeared with further milling time. When the milling time is longer than 40 h, the perovskite structure disappeared and the amorphous phase was formed completely. Scanning electron microscopy picture of 24 h milled sample showed that the particle size generally varies in a broad range from nanometer scale to a few μm. The magnetic measurements showed that ball milling samples have an inhomogeneous magnetic state and exhibit spin-glass like behavior. The significantly small magnetic entropy change and a remarkably broad temperature interval in entropy change were attributed to high degree of structural and magnetic disorder and broadening of magnetic transition. [ABSTRACT FROM AUTHOR]

In this study, the variation of the magnetic flux distribution in a magnetised ferromagnetic material which has in homogeneity as a crack is studied. An orthogonal fluxgate magnetic field sensor was used in the inspection of cracks. In the fluxgate sensor, the sensing element (Co0.94Fe0.06)72.5Si12.5B15 amorphous ferromagnetic wire was placed inside a pickup coil winding with 50 μm copper wire and connected to a signal generator and the output from pick-up coil was detected using a lock-in amplifier. The surface profile of magnetic materials with a crack was obtained using a specially designed 3-dimensional moving system. A large decrease in the output voltage of the sensor was observed when the sensor was moved on the top of the crack, after the further movement of the sensor the output voltage came back to the previous value. [ABSTRACT FROM AUTHOR]

In this work, the technological aspects of great importance YBa2Cu3O7-x superconducting materials were produced in the form of nanotube by electrochemical method. The electrochemical deposition conditions for the Y-Ba-Cu deposition in nanoporous Al2O3 were investigated. The heat treatment was applied to Y-Ba-Cu/Al2O3 nanopatterns, to form superconductive phase. The resulting nanostructures were found to be in length 4-5-m, 177-210 nm in diameter. The produced nanostructures at -4 V and more positive potentials were Y-Ba-Cu nanowires, while the nanostructures deposited at the more negative potentials were of nanotube form. [ABSTRACT FROM AUTHOR]

CoNiFe and NiFe nanowires were electrochemically produced by dc electrodeposition on highly ordered porous anodic alumina oxide templates. Scanning electron microscope images of nanowires after removing the alumina membrane showed that these nanowires are uniform with the diameters of about 220-300 nm and about 25-30 μm length. The energy dispersive X-ray analysis showed that the composition of the nanowires is Ni88Fe12, Co7Ni82Fe11. Magnetic field was applied by an electromagnet and resistance was measured by four point technique. [ABSTRACT FROM AUTHOR]

In this study, magnetic properties of Pr0.67Ca0.33MnO3 compound were investigated in detail. The magnetization versus temperature (M-T) curve showed that this material undergoes a charge order transition at 200 K. A more pronounced FM phase appeared below 56 K. At T = 5 K, a field induced sharp step like magnetisation transition associated with phase separation was observed. However, after application of 7 T magnetic field at 5 K, the magnetic behaviour of sample was changed completely and full FM behaviour was observed. The more interesting is that the sample remains in the FM state and does not retrieve the initial magnetic state until warmed up to charge order transition temperature. Large negative magnetic entropy change (-26.18 J/(kg K) at 38 K and 5 T) was attributed to step like magnetisation transition. [ABSTRACT FROM AUTHOR]