Enhanced Critical Currents of Superconducting <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>ErNi</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msub><mrow><mi>B</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mi>C</mi></math></span> in the Ferromagnetically Ordered State

P. L. Gammel; B. Barber; D. Lopez; A. P. Ramirez; D. J. Bishop; S. L. Bud'ko; P. C. Canfield

doi:10.1103/PhysRevLett.84.2497

Enhanced Critical Currents of Superconducting ${ErNi}_{2} B_{2} C$ in the Ferromagnetically Ordered State

P. L. Gammel, B. Barber, D. Lopez, A. P. Ramirez, D. J. Bishop, S. L. Bud'ko, and P. C. Canfield

Phys. Rev. Lett. 84, 2497 – Published 13 March 2000

Abstract

We report on transport and magnetization studies of the critical current in single crystal ${ErNi}_{2} B_{2} C$ for applied fields below 4 kG. Below $T \approx 2.5 K$ superconductivity coexists with weak ferromagnetism. We find that the critical currents are strongly enhanced for all field orientations in this ferromagnetic regime, corresponding to a threefold increase of the pinning force of the flux line lattice. We speculate that this increase is due to strong pair breaking by the ferromagnetism.