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Saini S.,Jeju National University | Kim G.S.,Jeju National University | Kim S.-J.,Research Institute of Advanced Technology
Journal of Superconductivity and Novel Magnetism | Year: 2010

To study the detailed characteristics of a nano-periodic Josephson junction array in a Bi 2Sr 2Ca 2Cu 3O 10+δ (Bi-2223) single crystal whisker without shunted grain boundaries, we fabricate a submicron stack with an area of 0.5 μm × 0.5 μm and height of approximately 200 nm using a focused ion beam (FIB) etching technique. The stack has several hundreds of elementary Josephson junctions along the c-axis. We fabricate the stack by rotation and tilt of the sample stage in the FIB. The current-voltage (I-V) characteristics give a well-defined superconducting gap (V g) and we notice suppression of the critical current in submicron junction with respect to big sized junction. We believe that the suppression of critical current in submicron junction is due to the normal resistance of the junction which belongs to the quantum resistance range. © Springer Science+Business Media, LLC 2010. Source


Uno K.,Ibaraki University | Ono T.,Ibaraki University | Shimizu I.,Research Institute of Advanced Technology
Optics Communications | Year: 2011

The analytical form for the reconstructed field of a hologram illuminated by a reference beam coded with a multicolored aperture array filter is derived. Experiments showed that the colored aperture array filter improved the quality of the reconstructed image by reducing the intensity of crosstalk images. Some parameters of the aperture array configuration that influence image quality were investigated. This technique presented here can be applied to full-color holographic displays and dot matrix holographic printers, etc. © 2010 Elsevier B.V. All rights reserved. Source


Hosaka S.,Gunma University | Mohamad Z.,Gunma University | Akahane T.,Gunma University | Yin Y.,Gunma University | And 5 more authors.
Advanced Materials Research | Year: 2012

We have studied the possibility to form fine magnetic column arrays using 30-keV-electron beam (EB) drawing with thin calixarene resist and 200-eV-Ar ion milling, and nanometer-sizing effect of the magnetic column on the corecive force for patterned media. We achieved 20-nm-sized resist dot arrays on PtCo magnetic and thin metals layers on glass substrate. We formed fine magnetic column arrays with a diameter of 39 to 106 nm and a space of about 100 nm using the resist pattern by the 200-eV Ar ion-milling. Using the nano magnetic column arrays, the hysteresis were measured by X-ray magnetic circular dichroism (XMCD) with an energy of 11.57 keV, which corresponds to an energy edge of Pt-L3. It is clarified that a coercive force of the nanometer-sized magnetic column increased as the diameter decreased. © (2012) Trans Tech Publications, Switzerland. Source


Hosaka S.,Gunma University | Mohamad Z.,Gunma University | Yin Y.,Gunma University | Sakurai H.,Gunma University | And 4 more authors.
Key Engineering Materials | Year: 2013

We have studied the coercive force of fine magnetic CoPt dot enhanced by nanometer-sizing of the dot. The 39- to 106-nm-sized CoPt magnetic dot arrays were formed by30-keV-electron beam (EB) drawing with thin calixarene resist and 200-eV-Ar ion milling. Using the fine magnetic dot arrays, we measured coercive forces of the dot by x-ray magnetic circular dichroism (XMCD) with an energy of 11.56 keV, which corresponds to an energy edge of Pt-L3. It is experimentally demonstrated that a coercive force of the nanometer-sized magnetic column increased as the dot diameter decreased. © (2013) Trans Tech Publications, Switzerland. Source


Kim S.-J.,Jeju National University | Kim S.-J.,Research Institute of Advanced Technology
Journal of Applied Physics | Year: 2011

A coupled stacked Josephson junctions (SJJs) with completely perforated holes of 0.2 m 0.4 m in high-Tc superconducting Bi2Sr 2CaCu2O8d (Bi-2212) were fabricated using a 3D focused ion beam etching method. We investigated external field angle i dependence of junction resistance Rj at various magnetic fields and temperatures. When a constant external magnetic fields He value of 1 T and a bias current Ib value of 1 A were applied to the sample with changing external field angle i, unspecified equidistant and periodic peak structures in the SJJs were induced. The periodic peaks of Rj shows the resistive switching transition from zero resistance state to resistance state. © 2011 American Institute of Physics. Source

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