Vortex pinning at low temperature under high magnetic field in SmBa₂Cu₃O_ysuperconducting films with high number density and small size of BaHfO₃nano-rods

Abstract

We have fabricated 5.6 vol.% BaHfO 3 (BHO)-doped SmBa 2 Cu 3 O y (SmBCO) films at a low substrate temperature of 750 °C by using the low temperature growth (LTG) technique with a seed layer. Using the LTG technique, we can obtain a purely c-axis oriented SmBCO film even at low growth temperatures. The LTG technique also greatly increases the number density of BHO nanorods. The size and matching field of the BHO nanorods in the films were 5.4 nm and 9.9 T. Transport measurements were carried out, and a high irreversibility field (B irr ) and strong flux pinning force density (F p ) were obtained. The B irr was 15.1 T at 77 K for B//c. The maximum F p of 407 GN m −3 in 10 T at 40 K and 770 GN m −3 from 9 to 17 T at 20 K have been measured. We believe that the LTG technique can be considered as important for improving of flux pinning performance in BaMO 3 (BMO: M=Zr, Sn and Hf)-doped SmBCO coated conductors.

Large pinning forces and matching effects in YBa2Cu3O7-δ thin films with Ba2Y(Nb/Ta)O6 nano-precipitates

“…The field  = μ 0 H ( F P,max ) at which the maximum pinning force density is reached increases with laser repetition rate (1.6 T for 1/2 Hz, 2.3 T for 1 Hz and 3.2 T for 5 Hz). Similar J c ( H ) curves have recently been reported for BaHfO 3 (BHO)-doped SmBa 2 Cu 3 O 7− δ 45. The pinning force density maximum for the 1 Hz sample (25 GN/m 3 for the 250 nm thick film at 77 K), Fig.…”

“…S6). The same correspondence between end of J c plateau, and has been observed for BHO-doped SmBa 2 Cu 3 O 7− δ /LAO45 and GdBa 2 Cu 3 O 7− δ /IBAD-MgO46.…”

“…240 nm BaSnO 3 -doped: 28.3 GN/m 3  12, 500 nm BYNO-doped: 32.3 GN/m 3 at 75.5 K25, 200 nm BaZrO 3 -doped: 21 GN/m 3  17). Other RE BCO films with slightly higher T c values doped with BHO (370 nm GdBCO: 23.5 GN/m 3  46, 300 nm SmBCO: 28 GN/m 3  45) show similar F P,max values at 77 K. The previously mentioned plateaus in J c ( H ) at 77 K also end at these fields . Furthermore, is temperature independent as can be seen by the dashed lines in Fig.…”

Deposition-Temperature Dependence of Vortex Pinning Property in YBa₂Cu₃O₇+BaHfO₃ Films

“…1820) The F p,max value of 15 GN/m 3 at 77 K is not so large compared with the results in the previous reports. On the other hand, the F p,max values of 400407 GN/m 3 have been observed in SmBCO+BHO at 40 K, 18,19) and the present F p,max value of 413 GN/m 3 at 40 K is one of the highest values. Thus, the high F p,max was successfully obtained especially at 40 K in the present YBCO+BHO(850).…”

“…6(b) shows the results for B¯= 47 T. Here, the result in Ref. 19 is excluded from Fig. 6(b) because its B¯of ³10 T is slightly larger than the B¯in Fig.…”