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A commercial stainless steel tube was employed to synthesize MgB2. The specimen was prepared by a stoichiometric mixture of Mg and B. The specimen that had been enveloped in the commercial stainless steel tube was synthesized for 2 hours at…

Superconductivity · Physics 2007-05-23 H. B. Lee , Y. C. Kim , B. J. Kim , D. Y. Jeong

We investigate spin-dependent conductance across a magnetic tunnel junction (MTJ) including a ferromagnetic insulating barrier. The MTJ consists of two half-metallic ferromagnetic La2/3Sr1/3MnO3 (LSMO) manganites as electrodes and La2NiMnO6…

Applied Physics · Physics 2022-12-09 M. Abbasi Eskandari , S. Ghotb , P. Fournier

$MgB_2$ becomes superconducting just below 40 K. Whereas porous polycrystalline samples of $MgB_2$ can be synthesized from boron powders, in this letter we demonstrate that dense wires of $MgB_2$ can be prepared by exposing boron filaments…

Electrolysis was carried out on fused mixtures of MgCl2, NaCl, KCl and MgB2O4 under an Ar flow at 600C. Electrical resistivity measurements for the grown deposits show an onset of superconducting transition at 37 K in the absence of applied…

Superconductivity · Physics 2009-11-07 Kenji Yoshii , Hideki Abe

We investigate tunneling in metal-insulator-metal junctions employing few atomic layers of hexagonal boron nitride (hBN) as the insulating barrier. While the low-bias tunnel resistance increases nearly exponentially with barrier thickness,…

Mesoscale and Nanoscale Physics · Physics 2019-03-26 U. Chandni , K. Watanabe , T. Taniguchi , J. P. Eisenstein

The study of the anisotropic superconductor MgB2 using a combination of scanning tunneling microscopy and spectroscopy reveals two distinct energy gaps at Delta1=2.3 meV and Delta2=7.1 meV. Different spectral weights of the partial…

Superconductivity · Physics 2009-11-07 M. Iavarone , G. Karapetrov , A. E. Koshelev , W. K. Kwok , G. W. Crabtree , D. G. Hinks

MgB2 thin films were deposited on SiC buffered Si substrates by sequential electron beam evaporation of B-Mg bilayer followed by in-situ annealing. The application of a SiC buffer layer enables the maximum annealing temperature of 830 C.…

Superconductivity · Physics 2009-11-11 S. Chromik , J. Huran , V. Strbik , M. Spankova , I. Vavra , W. Bohne , J. Rohrich , E. Strub , P. Kovac , S. Stancek

This letter presents experiments on junctions fabricated by a new technique that enables the use of high quality aluminum oxide tunnel barriers with normal metal electrodes at low temperatures. Inverse proximity effect is applied to…

Mesoscale and Nanoscale Physics · Physics 2013-03-27 J. V. Koski , J. T. Peltonen , M. Meschke , J. P. Pekola

We report the demonstration of hybrid high-Tc-superconductor-semiconductor tunnel junctions, enabling new interdisciplinary directions in condensed matter research. The devices were fabricated by our newly-developed mechanical bonding…

The break-junction tunneling has been systematically investigated in MgB2. Two types of the break-junction contacts have been exploited on the same samples, which demonstrated tunnel contact like (SIS) and point contact like (SnS) behavior.…

The MgB2 coated superconducting tapes have been fabricated on textured Cu (0 0 1) and polycrystalline Hastelloy tapes using coated conductor technique, which has been developed for the second generation high temperature superconducting…

Superconductivity · Physics 2015-06-03 Mahipal Ranot , W. N. Kang

High-density bulk materials of a newly discovered 40K intermetallic MgB2 superconductor were prepared by high pressure sintering. Superconducting transition with the onset temperature of 39K was confirmed by both magnetic and resistive…

Superconductivity · Physics 2009-11-07 Y. Takano , H. Takeya , H. Fujii , H. Kumakura , T. Hatano , K. Togano , H. Kito , H. Ihara

Superconducting tunnel junctions are being developed for application as photon detectors in astronomy. We present the latest results on the development of very high quality, very low critical temperature junctions, fabricated out of pure Al…

Superconductivity · Physics 2009-11-10 G. Brammertz , P. Verhoeve , D. Martin , A. Peacock , R. Venn

We investigate the spin-dependent transport of GaMnAs-based magnetic tunnel junctions (MTJs) containing a paramagnetic AlMnAs barrier with various thicknesses. The barrier height of AlMnAs with respect to the Fermi level of GaMnAs is…

Materials Science · Physics 2015-05-14 Shinobu Ohya , Iriya Muneta , Pham Nam Hai , Masaaki Tanaka

By imposing the constraints of structural compatibility, stability and a large tunneling magneto-resistance, we have identified the Fe$_3$Al/BiF$_3$/Fe$_3$Al stack as a possible alternative to the well-established FeCoB/MgO/FeCoB in the…

The two-dimensional atomically thin insulator hexagonal boron nitride (h-BN) constitutes a new paradigm in tunnel based devices. A large band gap along with its atomically flat nature without dangling bonds or interface trap states makes it…

Mesoscale and Nanoscale Physics · Physics 2014-11-14 André Dankert , M. Venkata Kamalakar , Abdul Wajid , R. S. Patel , Saroj P. Dash

We study the lateral tunneling through the gate-voltage-controlled barrier, which arises as a result of partial elimination of the donor layer of a heterostructure along a fine strip using an atomic force microscope, between edge channels…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. A. Shashkin , V. T. Dolgopolov , E. V. Deviatov , B. Irmer , A. G. C. Haubrich , J. P. Kotthaus , M. Bichler , W. Wegscheider

This letter describes a new inorganic shadow mask that has been employed for the evaporation of all-epitaxial Al/Al2O3/Al superconducting tunnel junctions. Organic resists that are commonly used for shadow masks and other lift-off processes…

Superconductivity · Physics 2012-03-28 Paul B. Welander , Vladimir Bolkhovsky , Terence J. Weir , Mark A. Gouker , William D. Oliver

Thin films of the recently discovered magnesium diboride (MgB2) intermetalic superconducting compound have been grown using a magnetron sputtering deposition technique followed by in-situ annealing at 830 C. High quality films were obtained…

Superconductivity · Physics 2009-11-07 R. Vaglio , M. G. Maglione , R. Di Capua

A new method for preparation of single crystals of the superconducting intermetallic MgB2 compound from a Mg-Cu-B melt flux is presented. The high vapour pressure of Mg at elevated temperature is a serious challenge of the preparation…

Superconductivity · Physics 2007-05-23 D. Souptel , G. Behr , W. Loser , W. Kopylov , M. Zinkevich