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High quality bulk MgB2 exhibit a structure of voids and agglomeration of crystals on different length-scales. Because of this, the superconducting currents percolate between the voids in the ensuing structure. Magnetic measurements reveal…

Superconductivity · Physics 2007-05-23 J. Horvat , S. Soltanian , A. V. Pan , X. L. Wang

The microstructures of MgB2 wires prepared by the powder-in-tube technique and subsequent hot isostatic pressing were investigated using transmission electron microscopy. Large amount of crystalline defects including small angle twisting,…

Materials Science · Physics 2009-11-10 X. Z. Liao , A. Serquis , Y. T. Zhu , L. Civale , D. L. Hammon , D. E. Peterson , F. M. Mueller , V. F. Nesterenko , Y. Gu

We have successfully prepared the MgB2 superconducting bulk and powdered materials by the method of combustion synthesis. The starting materials used in this study were powders of Mg and B. X-ray powder diffraction pattern was well assigned…

Superconductivity · Physics 2016-08-31 Yoshihiko Takano , Nobutaka Oguro , Yoshinari Kaieda , Kazumasa Togano

Since the discovery of superconductivity in MgB2 considerable progress has been made in determining the physical properties of the material, which are promising for bulk conductors. Tunneling studies show that the material is reasonably…

Superconductivity · Physics 2009-11-07 G. Burnell , D. -J. Kang , H. N. Lee , S. H. Moon , B. Oh , M. G. Blamire

Here we report the growth of sub-millimeter MgB2 single crystals of various shapes under high pressure in Mg-B-N system. Structure refinement using a single-crystal X-ray diffraction analysis gives lattice parameters a=3.0851(5) A and…

Superconductivity · Physics 2009-11-07 S. Lee , H. Mori , T. Masui , Yu. Eltsev , A. Yamamoto , S. Tajima

We demonstrate direct evidence of possible surface superconductivity on small, well-shaped MgB2 single crystals. Transport measurements in the range H < 1.6 Hc2^c, where Hc2^c is the bulk upper critical field for the c axis, show non-Ohmic…

High-pressure electrical resistivity measurements reveal that the mechanical deformation of ultra-hard WB2 during compression induces superconductivity above 50 GPa with a maximum superconducting critical temperature, Tc of 17 K at 90 GPa.…

The influence of two important features of magnesium diboride on the macroscopic transport properties of polycrystalline MgB2 is discussed in the framework of a percolation model. While two band superconductivity does not have significant…

Superconductivity · Physics 2011-03-24 M. Eisterer , H. W. Weber

We report synthesis, structure/micro-structure, resistivity under magnetic field [R(T)H], Raman spectra, thermoelectric power S(T), thermal conductivity K(T), and magnetization of ambient pressure argon annealed polycrystalline bulk samples…

Superconductivity · Physics 2015-05-13 V. P. S. Awana , Arpita Vajpaye , Monika Mudgel , H. Kishan , V. Ganesan , A. M. Awasthi , G. L. Bhalla

This review article describes the developments over the last 30 months in the thin film growth and junction fabrication of superconducting MgB2, including a brief summary the chemistry and physics of MgB2.

Superconductivity · Physics 2007-05-23 Michio Naito , Kenji Ueda

Materials of the Y-Ba-Cu-O (melt-textured YBa2Cu3O7-d-based materials or MT-YBCO) and Mg-B-O (MgB2-based materials) systems with high superconducting performance, which can be attained due to the formation of regularly distributed…

Crystal structures and microstructural features, such as structural phase transitions, defect structures, chemical and structural inhomogeneities, are known to have profound effects on the physical properties of superconducting materials.…

Superconductivity · Physics 2013-07-22 Wang Zhen , Cai Yao , Yang Huai-Xin , Tian Huan-Fang , Wang Zhi-Wei , Ma Chao , Chen Zhen , Li Jian-Qi

Finding viable superconducting materials is of interest to the physics community as the superconductors are the playground to manifest many appealing quantum phenomena. This work exemplifies an end-to-end materials discovery towards novel…

Superconductivity · Physics 2023-04-11 Ze Yu , Tao Bo , Bo Liu , Zhendong Fu , Huan Wang , Sheng Xu , Tianlong Xia , Shiliang Li , Sheng Meng , Miao Liu

MgB2 superconducting wires were produced by the Mg diffusion method. Scanning electron microscopy (SEM), optical microscopy, dispersive x-ray analysis (EDS) and XRD diffraction were used to study the physical structure and content of the…

Superconductivity · Physics 2009-11-10 Maya Bar-Sadan , Gregory Leitus , Shimon Reich

The proximity effect in normal/superconductor heterostructures is an intriguing phenomenon in that the normal side takes on the properties of a superconductor with an induced gap. However, the structural and pinning properties of vortices…

Precise structural information on the Mg1-xAlxB2 superconductors in the vicinity of x 0.5 is derived from high-resolution synchrotron X-ray powder diffraction measurements. We find that a hexagonal superstructure, accompanied by doubling of…

Materials Science · Physics 2009-11-07 S. Margadonna , K. Prassides , I. Arvanitidis , M. Pissas , G. Papavassiliou , A. N. Fitch

The discovery of superconductivity at 39 K in MgB2[1] raises many issues. One of the central questions is whether this new superconductor resembles a high-temperature-cuprate superconductor or a low-temperature metallic superconductor in…

The system MgxB2 has been investigated to investigate possible nonstoichiometry in MgB2. When synthesized at 850oC, MgB2 is a line compound with a possible Mg vacancy content of about 1%. Small changes in lattice constants as a function of…

Superconductivity · Physics 2009-11-07 D. G. Hinks , J. D. Jorgensen , Hong Zheng , S. Short

The synthesis of MgB2-based materials under high pressure gave the possibility to suppress the evaporation of magnesium and to obtain near theoretically dense nanograined structures with high superconducting, thermal conducting, and…

In this letter, we report the first successful fabrication of dense, metal-clad MgB2 superconductor wires as well as the first demonstration of high transport Jc of greater than 36,000 A/cm2 in MgB2. The fabrication technique that we…

Superconductivity · Physics 2007-05-23 S. Jin , H. Mavoori , R. B. van Dover