Pinning Force Scaling Analysis of Polycrystalline MgB2

Abstract

Flux pinning force scaling $f=F_{p}/F_{p,\max \limits }$ f = F p / F p , max vs. h = Ha/Hirr was performed on a variety of pure MgB2 samples, including a spark plasma sintered (SPS) one and a series of samples sintered at various reaction temperatures ranging between 775 and 950 ∘C. The SPS sample exhibits a well-developed scaling at all temperatures, and also the sintered samples prepared at 950 ∘C; however, the obtained peak positions of the pinning force scalings are distinctly different: The SPS sample reveals dominating pinning at grain boundaries, whereas the dominating pinning for the other one is point-pinning. All other samples studied reveal an apparent non-scaling of the pinning forces. The obtained pinning parameters are discussed in the framework of the Dew–Hughes’ pinning force scaling approach.

New Scaling Laws for Pinning Force Density in Superconductors

“…This is the primary reason for the widely accepted deduction [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]24,25] of the pparameter of Equation (3), which is the primary value in Kramer-Dew-Hughes scaling laws [2,3]…”

Computational Study of Field-Dependent Pinning Force for Pure MgB2 Superconductor

“…Furthermore, Fietz and Webb proposed the one power scaling law for normalized pinning force density to recognize the nature of pinning boundaries [8]. Pinning force scaling force analysis was performed in pure MgB2 samples with a wide range of temperatures including a spark plasma sintered one [9]. The elementary pinning force of grain boundaries is calculated using the electron scattering process and the residual resistivity [10].…”