Chiral Materials and Unconventional Superconductivity Group
Isotropic HTS materials
HTS materials are intrinsically isotropic. In 2006 our group at BNL was the first to demonstrate experimentally that high field, low anisotropy YBCO can indeed be fabricated [1]. Unlike traditional YBCO material, isotropic YBCO has virtually flat angular dependence of the critical current in magnetic fields up to 4 Tesla, which is reflected by low a anisotropy factor of gamma = 1.5, as compared to gamma= 7 for standard YBCO, see figure below. Having low anisotropy is very desirable for the design of high-field devices. Exact nature of the isotropic behavior is still debated and is a matter of on-going research.
Anisotropy of the critical current density at 77 Kelvin of BNL isotropic YBCO material (left panel) compared to standard YBCO deposited by pulsed-laser deposition at Los Alamos National Laboratory (right panel).
References
- Superconductor Science and Technology, vol. 20 (2007), pp: L20-L23, "High critical currents by isotropic magnetic-flux-pinning centres in a 3 µm-thick YBa2Cu3O7 superconducting coated conductor", Solovyov V F, Wiesmann H J, Wu L, Li Q, Cooley L D, Suenaga M, Maiorov B, and Civale L.
