Exponential critical-state model for magnetization of hard superconductors
- Electromagnetism Group, Department of Physics, Universitat Autonoma Barcelona, 08193 Bellaterra, Spain (ES)
We have calculated the initial magnetization curves and hysteresis loops for hard type-II superconductors based on the exponential-law model, {ital J}{sub {ital c}}({ital H}{sub {ital i}}) ={ital k} exp({minus}{vert bar}{ital H}{sub {ital i}}{vert bar}/{ital H}{sub 0}), where {ital k} and {ital H}{sub 0} are constants. After discussing the general behavior of penetrated supercurrents in an infinitely long column specimen, we define a general cross-sectional shape based on two equal circles of radius {ital a}, which can be rendered into a circle, a rectangle, or many other shapes. With increasing parameter {ital p} (={ital ka}/{ital H}{sub 0}), the computed {ital M}-{ital H} curves show obvious differences with those computed from Kim's model and approach the results of a simple infinitely narrow square pulse {ital J}{sub {ital c}}({ital H}{sub {ital i}}). For high-{ital T}{sub {ital c}} superconductors, our results can be applied to the study of the magnetic properties and the critical-current density of single crystals, as well as to the determination of the intergranular critical-current density from magnetic measurements.
- OSTI ID:
- 6963217
- Journal Information:
- Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 67:7; ISSN 0021-8979; ISSN JAPIA
- Country of Publication:
- United States
- Language:
- English
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