TY - JOUR
T1 - Rapid and simple measurement of critical current density in HTS thin films using a permanent magnet method
AU - Saito, A.
AU - Takeishi, K.
AU - Takano, Y.
AU - Nakamura, T.
AU - Yokoo, M.
AU - Mukaida, M.
AU - Hirano, S.
AU - Ohshima, S.
N1 - Funding Information:
This research was partially supported by CREST of Japan Science and Technology corporation, Yamagata prefecture, the Ministry of Education, Culture, Sports, Science and technology, Grant-in-Aid for Young Scientists (B), 16760019, 2004. A part of this work was carried out in the clean room of Yamagata University. The authors would like to acknowledge Dr. T. Manabe of AIST Japan for preparing a part of the HTS samples fabricated by a MOD process.
PY - 2005
Y1 - 2005
N2 - We present the results of non-destructive and contactless measurement of the critical current density (Jc) of high-temperature superconductor (HTS) thin films using a permanent magnet method. A cylindrical permanent magnet (Sm2Co17) with a height of 5.0 mm and diameter d of 5.0 mm was used. To investigate the margin of the sample setting for the vertical direction, load vs. distance curves for a minimum distance Lmin which varied from 0.5 to 2.0 mm were measured. Here, L is the distance from the permanent magnet to a surface of the HTS film. The effective maximum repulsive force Fm,eff was almost constant below Lmin = 1.2 mm. This result indicates that the measurement system has a wide margin with respect to sample setting in the vertical direction. We investigated the dependence of Fm,eff on the sample area from diameter l = 20-4 mm and found that the relationship of the critical current density Jc = 1.7 × 10-7 (Fm,eff/t) can be applied for l/d > 2 and the required sample size of the HTS films is approximately l = 2d for this system. Here, t is the thickness of the HTS thin film. These results indicate that the permanent magnet method can be used to easily estimate the Jc of HTS films at 77 K. Additionally, this system has good reproducibility for J c measurements. It is thus promising as a replacement for conventional inductive measurements and for measurements for Jc mapping of HTS films, tapes, and wires using a small magnet.
AB - We present the results of non-destructive and contactless measurement of the critical current density (Jc) of high-temperature superconductor (HTS) thin films using a permanent magnet method. A cylindrical permanent magnet (Sm2Co17) with a height of 5.0 mm and diameter d of 5.0 mm was used. To investigate the margin of the sample setting for the vertical direction, load vs. distance curves for a minimum distance Lmin which varied from 0.5 to 2.0 mm were measured. Here, L is the distance from the permanent magnet to a surface of the HTS film. The effective maximum repulsive force Fm,eff was almost constant below Lmin = 1.2 mm. This result indicates that the measurement system has a wide margin with respect to sample setting in the vertical direction. We investigated the dependence of Fm,eff on the sample area from diameter l = 20-4 mm and found that the relationship of the critical current density Jc = 1.7 × 10-7 (Fm,eff/t) can be applied for l/d > 2 and the required sample size of the HTS films is approximately l = 2d for this system. Here, t is the thickness of the HTS thin film. These results indicate that the permanent magnet method can be used to easily estimate the Jc of HTS films at 77 K. Additionally, this system has good reproducibility for J c measurements. It is thus promising as a replacement for conventional inductive measurements and for measurements for Jc mapping of HTS films, tapes, and wires using a small magnet.
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U2 - 10.1016/j.physc.2005.02.095
DO - 10.1016/j.physc.2005.02.095
M3 - Conference article
AN - SCOPUS:25644439888
SN - 0921-4534
VL - 426-431
SP - 1122
EP - 1126
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
IS - II
T2 - Proceedings of the 17th Internatioanl Symposium on Superconductivity (ISS 2004) Advances in Superconductivity
Y2 - 23 November 2004 through 25 November 2004
ER -