critical current density

critical current density

[′krid·ə·kəl ′kər·ənt ‚den·səd·ē]
(physical chemistry)
The amount of current per unit area of electrode at which an abrupt change occurs in a variable of an electrolytic process.
References in periodicals archive ?
Compared with the calculated value of the critical amplitude density [[delta].sub.CC1] used in the experiment the damped sinusoidal current pulse [i.sub.p](t) which equals to [[delta].sub.CC1] [approximately equal to] [I.sub.mp]/[S.sub.CC1] [approximately equal to] 205 kA/3.34 [mm.sup.2] [approximately equal to] 61.4 kA/[mm.sup.2], the obtained experimental value of the critical current density [[delta].sub.CC1] differs from it by about 8 %.
With the development in the properties of high temperature superconducting (HTS) conductors, the HTS magnet could be considered as potential Tokamak magnet components with the advantages of higher operation temperature and critical current density [1-3].
Similarly, Zhao and coworkers have found that the calculated diffusion coefficient for solid Ni in liquid Al increases with increasing current density under DC and approaches a relatively stable value at a certain critical current density, regardless of current polarity [23].
Hirabayashi, "High critical current density in Y-Ba-Cu-O bulk superconductors with very fine Y211 particles," Superconductor Science and Technology, vol.
The inductive current far exceeds critical current density of the superconductor, thus causing rapid, within several milliseconds, and uniform transition of the device from zero-resistance to high-resistance state, effectively limiting the fault current to no more than 20% of the nominal current.
The US patent titled 'Enhancing Critical Current Density of Cuprate Superconductors' reveals a method for improving the critical current density in superconductors by restricting the movement of Abrikosov (A) vortices, Josephson (J) vortices, or Abrikosov-Josephson (A-J) vortices using the half integer vortices associated with the d-wave symmetry present in the grain boundary.
In comparison to low-temperature superconducting wire, which is already being used for MRI, NMR, linear motorcars and more, high-temperature superconducting wire has a higher critical current density (size of electric current), lowers costs by using liquid nitrogen for cooling, and reduces susceptibility to the effects of external magnetic fields, so the development of high-temperature superconducting wire is currently being promoted.
The 32 papers consider such topics as possibilities of graphene application in textronic devices, the elucidation of metal diffusion mechanisms in conducting-bridge random access memory using first-principle calculations, doped hafnium oxide as an enabler for ferroelectric field effect transistors, and critical current density and pinning energy of a partially melted samarium-based superconductor.
Among the cuprate high-[T.sub.c] materials, the Bi(Pb)-Sr-Cu-0 are considered to be the most promising candidates for various reasons, in particular for their rather high critical temperature T[T.sub.c], high critical current density [J.sub.c] and power transmission in electric cables at liquid nitrogen temperatures.
Sediqeh Dadras, the faculty member of Alzahra University in Tehran, et al increased the critical current density of high temperature superconductor YBCO up to 10 times by using CNT.This doping also resulted in pinning energy increase, no decrease in critical transient temperature, and Hall coefficient sign reversal of CNT doped samples.Carbon nanotubes and high temperature superconductor YBCO were synthesized by CVD and solid state reaction methods respectively and CNT doped high temperature superconductor YBCO was finally manufactured at Alzahra University.Electrical and magnetic tests and measurements were conducted in cooperation with Prof.
One major obstacle to this is the degradation of the critical current density, [J.sub.c], under an applied magnetic field due to the relatively weak flux pinning observed in pure Mg[B.sub.2] crystals.
Other topics include thermal transients in MgB2 conductors, theories of peak effect and anomalous Hall effect, doping effects on the superconducting properties of bulk and PIT MgB2, optimizing critical current density, and microwave response of ceramic samples.

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