Related papers: Upper critical fields of MgB2 thin films
Biaxially textured LuNi2BC thin films with Tc up to 15.8 K and a residual resistivity ratio up to 15 have been prepared. The films were deposited on MgO(110) substrates using pulsed laser deposition from a stoichiometric target. Via the…
Superconducting MgB2 thin films were prepared on 50-micrometer-thick, flexible polyamide Kapton-E foils by vacuum co-deposition of Mg and B precursors with nominal thickness of about 100 nm and a special ex-situ rapid annealing process in…
We have measured the longitudinal resistivity and the Hall resistivity in the ab-plane of highly c-axis-oriented MgB2 thin films. In the normal state, the Hall coefficient (R_H) behaves as R_H ~ T with increasing temperature (T) up to 130 K…
High-grade MgB2(0001) films were grown on Mg(0001) by means of ultra-high-vacuum molecular beam epitaxy. Low energy electron diffraction and x-ray diffraction data indicate that thick films are formed by epitaxially oriented grains with…
The high field magnetization and magneto transport measurements are carried out to determine the critical superconducting parameters of MgB2-xCx system. The synthesized samples are pure phase and the lattice parameters evaluation is carried…
The intrinsic properties of MgB$_2$ form the basis for all applications of this superconductor. We wish to emphasize that the application range of polycrystalline MgB$_2$ is limited by the upper critical field H$_{c2}$ and its anisotropy.…
We present a detailed numerical calculation of the upper critical field $H_{c2}(T)$ for a bulk extreme type-II superconductor. Particular emphasis is placed on the high-field, low-temperature regime of the HT-phase diagram. In this regime…
We use magnetoresistance measurements at high magnetic field (B \leq 65 T) and low temperature (T \geq 500 mK) to gain fresh insights into the behavior of the upper critical field, Hc2, in superconducting ultrathin FeSe films of varying…
We investigate the upper critical field in a dirty two-band superconductor within quasiclassical Usadel equations. The regime of very high anisotropy in the quasi-2D band, relevant for MgB$_{2}$, is considered. We show that strong…
The microscopic superconductivity theory in MgB2 systems in the magnetic fields directed parallel and perpendicular to the plane (ab) is built. The two energy bands of different dimensions overlapping on the Fermi surface (two-dimensional…
We have studied the effect of damage induced by 2-MeV alpha particles on the critical temperature, Tc, and resistivity of MgB2 thin films. This technique allows defects to be controllably introduced into MgB2 in small successive steps. Tc…
The influence of the initial MgB2 grain size on critical current density, upper critical fields and irreversibility has been studied on Fe sheathed monofilamentary MgB2 tapes prepared by the Powder-In-Tube technique. The effect of the…
Magnesium diboride has many intriguing characteristics, including its relatively high critical temperature and two-band nature. Most prior studies of MgB2 thin film Josephson junctions have been conducted above 2 Kelvin. We report results…
A brief review of works on the microscopic theory of determining the upper critical field in two-band isotropic and anisotropic superconductors is given. The research is based on a set of the Ginzburg-Landau equations for the order…
The lower critical field $H_{c1}$ has been carefully measured on a well shaped cylindrical sample of the new superconductor $MgB_2$ fabricated by high pressure synthesis. The penetration depth $\lambda$ is calculated from the $H_{c1}$ data.…
We have successfully deposited thick MgB2 film on the (0001) crystalline surface of sapphire by the method of hybrid physical-chemical vapor deposition (HPCVD). The film thickness is about 1.3 micron. It has a dense and interlaced…
The microwave response of high quality niobium films in a perpendicular static magnetic field has been investigated. The complex frequency shift was measured up to the upper critical fields. The data have been analyzed by the effective…
The orbital upper critical field $H_{c2} $ is evaluated for isotropic materials with arbitrary transport and pair-breaking scattering rates. It is shown that unlike transport scattering which enhances $H_{c2} $, the pair breaking suppresses…
The high transition temperature and low surface resistance of MgB2 attracts interest in its potential application in superconducting radio frequency accelerating cavities. However, compared to traditional Nb cavities, the viability of MgB2…
Studies on the new MgB2 superconductor, with a critical temperature Tc ~ 39 K, have evidenced its potential for applications although intense magnetic relaxation effects limit the critical current density, Jc, at high magnetic fields. This…