Peak effects in NbSe<sub>2</sub> with artificial pinning centers
ORAL
Abstract
Irradiations of swift particles into superconductors modify their vortex states and lead to the enhancement of critical current density, Jc, via creation of point defects (PDs) or columnar defects (CDs). Such an enhancement of Jc was demonstrated in cuprate superconductors [1] as well as in conventional [2] and iron-based superconductors [3]. However, how the Jc is enhanced depends strongly on the target material and ion species, energy, and density of swift particles. In some cases, Jc is monotonically enhanced, while in other cases, non-monotonic magnetic field dependence of Jc, peak effect, is observed after the irradiation. In the present study, we compare the effect of PDs and CDs on the Jc - H behavior of NbSe2. With increasing the density of PDs by proton irradiation, the field range for the peak effect close to Hc2 broadens significantly. In the case of CDs, the Jc - H behavior changes sensitively as a function of the direction of CDs and magnetic field with respect to the c-axis.
[1] L. Civale et al., Phys. Rev. Lett. 67, 648 (1991).
[2] P. Bauer et al., Europhys Lett. 23, 585 (1991).
[3] Y. Nakajima et al., Phys. Rev. B 80, 012510 (2009).
[1] L. Civale et al., Phys. Rev. Lett. 67, 648 (1991).
[2] P. Bauer et al., Europhys Lett. 23, 585 (1991).
[3] Y. Nakajima et al., Phys. Rev. B 80, 012510 (2009).
*This work is partially supported by a Grant-in-Aid for Scientific Research (A) (Grant No. 17H01141) by JSPS.
–
Presenters
-
Tsuyoshi Tamegai
- Department of Applied Physics, The University of Tokyo
- Department of Applied Physics, University of Tokyo