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Abstract |
We study the effective profile of the pinning potential well in Bi$2$Sr$2$CaCu$_2$O8+δ single crystals using transverse ac magnetic susceptibility. The results show that the harmonic approximation for the potential well (linear regime) is valid up to vortex displacements $r\simeqξ$, where ξ, is the coherence length. In spite of this, it is necessary to induce displacements of the vortex structure much larger than ξ to depin it from its potential. This is shown to take place even in the single vortex limit. |
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