Progress in development of MOCVDbased coated conductors

Transcription

1 Progress in development of MOCVDbased coated conductors Venkat Selvamanickam, Y. Yao, Y. Liu, J. Liu, N. Khatri, E. Galtsyan, and dg. Majkic Department of Mechanical Engineering g Texas Center for Superconductivity University of Houston, Houston, TX, USA Y. Chen and C. Lei SuperPower Inc., Schenectady, NY, USA Funded by Advanced Research Projects Agency-Energy (ARPA-E) award DE-AR Applied Superconductivity Conference, Portland, OR, October 8 12,

2 4X HTS conductor performance improvement targeted for high power wind generators Improved approaches to engineer nanoscale defects in coated conductors in ARPA-E funded program. New pilot MOCVD system set up in UH Energy Research Park to rapidly scale up new technology advances to long-length manufacturing. Engineered nanoscale defects High-power, Efficient Wind Turbines 4x improved wire manufacturing Quadrupling superconductor Performance at 30 K, 2.5 T for commercialization of 10 MW wind generators to reduce wire cost by 4x Advances will also lead to high-performance HTS conductors for other high-field applications

3 4X HTS conductor can enable commercial feasibility of HTS devices Metric Now End of project Critical current at 30 K, 2.5 T (A/12 mm) (device operating condition) 750 ~3000 Wire price at device operating condition ($/ka-m) Estimated HTS wire required for a 10 MW generator (m) 65,000 16,250 Estimated HTS wire cost for a 10 MW generator $ (,000) 7,020 1,755 Quadruple the critical current performance to 3,000 A at 30 K and 2.5 T Doubling the lift factor (ratio of I c at operating temperature and field to I c at 77 K, zero field) in I c of coated conductors at 30 K, 2.5 T by engineering nanoscale defect structures in the superconducting film. Additional near doubling of critical current by thicker superconducting films while maintaining the efficacy of pinning by nanostructures. 3

4 In-field I c of today s coated conductor previously improved by 2x by Zr addition 0 T) J c (B) / J c (77 K, B tape Magnetic Field (T) 77 K, 7.5% 77 K, 0% 65 K, 7.5% 65 K, 0% 50 K, 7.5% 50 K, 0% 40 K, 7.5% 40 K, 0% 30 K, 7.5% 30 K, 0% 20 K, 7.5% 20 K, 0% Lift Factor of Lift factor of Field & 77 K, zero field I c Zr-doped Temperature tape is Undoped Zr-doped higher by 65 K, 3 T K, 3 T K, 3 T K, 3 T K, 3 T At 3 T, over a wide range of temperatures, quantity of HTS conductor required for device is reduced by ½ which greatly improves the economics of the device. Goal is to achieve another 2x improvement in lift factor at 30 K, 2.5T

5 Opportunities to further improve pinning with higher density of BZO defects in high Zr content tapes 7.5%Zr 15%Zr BZO spacing in 7.5%Zr sample : 35 nm BZO spacing in 15%Zr sample : 17 nm

6 Crit tical curren nt (A/12 mm m) Degradation in 77 K performance at higher Zr doping levels K, 0 T Ic Tc % 5% 10% 15% 20% 25% Zr content t (%) (K) T c Zero-field critical current drops beyond 7.5% Zr addition. Sharper drop in T c beyond 10% Zr addition (3 K from 10% - 25%) HTS process Optimal BZO content Reference PLD 5 mol.% SUST 22, (2009) MOD 10 mol% SUST 24, (2011) MOCVD 7.5 Zr% Physica C. 469, 2037 (2009) Based three different HTS deposition techniques, optimal BZO content for best performance at 77 K, 1 T is less than 10 mol.% How to employ high levels of BZO (>> 10%) to introduce high density of nanoscale defects and still achieve good performance?

7 Deterioration in superconductor quality with increasing Zr content 25% BZO 15% BZO 7.5% BZO 0% BZO (006) (005) (200) RE 2 O 3 (002)

8 MOCVD process improved to achieve much better REBCO film crystallinity at high Zr levels (006) MgO (200) (005) RE 2 O 3 (200) (002) LMO (200) BZO (200) (103) Previous process: 15%Zr Improved process : 15%Zr

9 Significant improvement in 77 K performance of tapes with high levels of Zr addition by modified MOCVD process T c (K) Tc ΔTc % 10% 15% 20% 25% 30% Zr addition ΔT c (K) mm) Critical cur rrent (A/ Standard Process Modified Process 77 K, zero field 0% 5% 10% 15% 20% 25% 30% Zr content Opportunity to now to benefit from high defect density with high levels of Zr addition 9

10 Significant improvement in performance of 15% Zr-added d tapes with modified d MOCVD process Critica al current (A/12 mm) % Zr 15% Zr modified process Angle between magnetic field and tape normal ( ) 30 K, 3 T % Zr current (A A/12 mm) Critical K, B tape 15%Zr, modified process Magnetic field (T) Critical current of 15% Zr-added film ~ 1100 A/12 mm at 30 K, 3 T, B c Lift factor at 30K, 3 T, B c improved by 40-65%

11 High critical currents in thick films of 15%Zradded GdYBCO tapes Critical curre ent (A/12 mm m) Jc (MA A/cm 2 ) Intens 1.E+05 sity 1.E+04 1.E+03 LMO (200) (006) (200) 1 µm 2 µm 3 µm 4 µm 5 µm HTS film thickness (µm) 0 1.E theta ( ) Combining thick film and improved pinning compositions to achieve high critical currents in high magnetic fields. No significant a-axis oriented growth found even in 5 µm thick films 11

12 No significant change in microstructure even up to 5 µm HTS film thickness in 15%Zr films 1 µm 2 µm 2µm 2µm 3 µm 4 µm 5 µm 2µm 2µm 2µm

13 Crit tical curren nt (A/cm) Ultra-high critical currents in 15%Zr-added thick film tapes in high magnetic fields at 4.2K X 42K 4.2K, B c 15%Zr, 3 µm 7.5%Zr, 1.1 µm 0%Zr, 1.1 µm Magnetic Field (T) c (B) / J c (77 7 K, 0 T) J c K, B c 15%Zr, 3 µm 7.5%Zr, 1.1 µm Magnetic Field (T) Measurements by J. Jaroszynski, D. Abraimov, X. Hu and D. Larbalestier, NHMFL I c = 3385 A/cm at 4.2 K, 5 T (B c), 2.8 times higher h than previous best Improvement from pinning (lift factor) is 25% higher in 15%Zr-tape at 4.2 K, 5 T (B c) than previous-best 7.5%Zr-added tape 13

14 Several opportunities to further improve in- field performance Increase density of nanoscale defects Introduce nanoscale defects that are even more effective at low temperatures and high fields Modify growth process for longer nanorods without interruptions 5 nm Average size 3.9nm Average distance ~12nm 14

15 Interruptions to vertical nanorods by defects along the a-b plane: Opportunity to improve 100 nm 20 nm

16 High density of BZO nanorods over entire film thickness without interruptions possible 100 nm 20 nm No significant ifi in-plane defects to interrupt t BZO nanorods along c-axis. 77 K, zero-field critical current needs to be improved

17 Upcoming papers of the Houston Group at ASC Improved pinning and critical currents in coated conductors Y. Liu, 4MJ-05, Thu, Oct 11, 4:30-6:30 PM; Electromagnetic properties of high-zr content GdYBCO tapes Y. Chen, 4MJ-01, Thu, Oct 11, 4:30-6:30 PM; Interaction between BaZrO 3 and RE 2 O 3 pinning centers in Zr:GdYBCO HTS tapes G. Majkic, 3MPE-05, Wed, Oct 10, 9:00-10:30 AM; Effect of High BZO Dopant Levels on Performance of 2G-HTS MOCVD Wire at Intermediate and Low Temperatures C. Lei, 2ME-05, Tue, Oct 9, 3:30-5:30 PM; The structural evolution of (Gd,Y)BaCuO tapes with Zr addition made by metal organic chemical vapor deposition N. D. Khatri, 2MA-02, Tue, Oct 9, 10:30 AM - 12:30 PM; Pre-fabricated Metal Nanorods on Biaxially-textured Substrates for REBCO Pinning Superconductors Low ac loss coated conductors I. Kesgin, 3LPS-03 03, Wed, Oct 10, 2:00-3:30 PM; Effect of Selectively Electrodeposited Stabilizer Thickness on AC Loss Behavior of Fully-Filamentized 2G-HTS Wire X. Cai, 3MPE-01, Wed, Oct 10, 9:00-10:30 AM; Completely Etch-free Fabrication of Multifilamentary 2G-HTS Tapes Using Inkjet Printing and Electrodeposition Delamination in coated conductors E. Galstyan, 4MPC-01, Thu, Oct 11, 9:00-10:30 AM. Investigation of Delamination Mechanisms in REBCO Coated Conductors 17