The pinning characteristics of a single crystal NdBaaCu3Oy superconductor at low （40 K）, intermediate （77.3 K） and high （88 K） temperatures were investigated. The experimental results of the critical current den...The pinning characteristics of a single crystal NdBaaCu3Oy superconductor at low （40 K）, intermediate （77.3 K） and high （88 K） temperatures were investigated. The experimental results of the critical current density dc and the apparent pinning potential u o which estimated from magnetic relaxation measurements are compared with the theoretical analysis based on the flux creep-flow model, taking the distribution of the flux pinning strength into account. The number of flux lines in the flux bundle （g2）, the most probable value of pinning strength （Am）, distribution width of pinning strength （σ-2） and other pinning parameters such as m, γ,δ are determined so that a good fit is obtained between the experimental and theoretical results. The behavior of these parameters is discussed in correspondence to the pinning characteristics of low, intermediate and high temperatures. The observed results are approximately consistent with the theoretical predictions of Brandt et al. model of the order-disorder transition.展开更多
文摘The pinning characteristics of a single crystal NdBaaCu3Oy superconductor at low （40 K）, intermediate （77.3 K） and high （88 K） temperatures were investigated. The experimental results of the critical current density dc and the apparent pinning potential u o which estimated from magnetic relaxation measurements are compared with the theoretical analysis based on the flux creep-flow model, taking the distribution of the flux pinning strength into account. The number of flux lines in the flux bundle （g2）, the most probable value of pinning strength （Am）, distribution width of pinning strength （σ-2） and other pinning parameters such as m, γ,δ are determined so that a good fit is obtained between the experimental and theoretical results. The behavior of these parameters is discussed in correspondence to the pinning characteristics of low, intermediate and high temperatures. The observed results are approximately consistent with the theoretical predictions of Brandt et al. model of the order-disorder transition.
