Observation of the spontaneous vortex phase in the weakly ferromagnetic superconductor ErNi$_{2}$B$_{2}$C: A penetration depth study

Elbert E. M. Chia; M. B. Salamon; Tuson Park; Heon-Jung Kim; Sung-Ik Lee; Hiroyuki Takeya

doi:10.1209/epl/i2005-10465-7

paper

Observation of the spontaneous vortex phase in the weakly ferromagnetic superconductor ErNi $_{2}$ B $_{2}$ C: A penetration depth study

arXiv:cond-mat/0409521 · doi:10.1209/epl/i2005-10465-7

Abstract

The coexistence of weak ferromagnetism and superconductivity in ErNi $_{2}$ BC suggests the possibility of a spontaneous vortex phase (SVP) in which vortices appear in the absence of an external field. We report evidence for the long-sought SVP from the in-plane magnetic penetration depth $Δ λ (T)$ of high-quality single crystals of ErNi $_{2}$ B $_{2}$ C. In addition to expected features at the Néel temperature $T_{N}$ = 6.0 K and weak ferromagnetic onset at $T_{W F M} = 2.3$ K, $Δ λ (T)$ rises to a maximum at $T_{m} = 0.45$ K before dropping sharply down to $\sim$ 0.1 K. We assign the 0.45 K-maximum to the proliferation and freezing of spontaneous vortices. A model proposed by Koshelev and Vinokur explains the increasing $Δ λ (T)$ as a consequence of increasing vortex density, and its subsequent decrease below $T_{m}$ as defect pinning suppresses vortex hopping.

arXiv comment5 pages including figures; added inset to Figure 2; significant revisions to text

Observation of the spontaneous vortex phase in the weakly ferromagnetic superconductor ErNi $_{2}$ B $_{2}$ C: A penetration depth study

Abstract

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Observation of the spontaneous vortex phase in the weakly ferromagnetic superconductor ErNi2​B2​C: A penetration depth study

Abstract

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Cited by in corpus (4)

Observation of the spontaneous vortex phase in the weakly ferromagnetic superconductor ErNi $_{2}$ B $_{2}$ C: A penetration depth study