RT Journal Article
T1 Equal-spin Andreev reflection and long range coherent transport in hightemperature superconductor/half-metallic ferromagnet junctions
A1 Visani, Cristina
A1 Sefrioui Khamali, Zouhair
A1 Tornos Castillo, Javier
A1 Villegas Hernández, Javier Eulogio
A1 León Yebra, Carlos
A1 Briatico, J.
A1 Bibes, Manuel
A1 Barthelemy, Agnes
A1 Santamaría Sánchez-Barriga, Jacobo
AB Conventional superconductivity is incompatible with ferromagnetism, because the magnetic exchange field tends to spin-polarize electrons and breaks apart the opposite-spin singlet Cooper pairs(1). Yet, the possibility of a long-range penetration of superconducting correlations into strong ferromagnets has been evinced by experiments that found Josephson coupling between superconducting electrodes separated afar by a ferromagnetic spacer(2-7). This is considered a proof of the emergence at the superconductor/ferromagnetic (S/F) interfaces of equal-spin triplet pairing, which is immune to the exchange field and can therefore propagate over long distances into the F (ref. 8). This effect bears much fundamental interest and potential for spintronic applications(9). However, a spectroscopic signature of the underlying microscopic mechanisms has remained elusive. Here we do show this type of evidence, notably in a S/F system for which the possible appearance of equal-spin triplet pairing is controversial(10-12): heterostructures that combine a half-metallic F (La0.7Ca0.3MnO3) with a d-wave S (YBa2Cu3O7). We found quasiparticle and electron interference effects in the conductance across the S/F interfaces that directly demonstrate the long-range propagation across La0.7Ca0.3MnO3 of superconducting correlations, and imply the occurrence of unconventional equal-spin Andreev reflection. This allows for an understanding of the unusual proximity behaviour observed in this type of heterostructures(12,13).
PB Nature Research
YR 2012
FD 2012-05-13
LK https://hdl.handle.net/20.500.14352/97161
UL https://hdl.handle.net/20.500.14352/97161
LA eng
NO Visani, C., Sefrioui, Z., Tornos, J. et al. Equal-spin Andreev reflection and long-range coherent transport in high-temperature superconductor/half-metallic ferromagnet junctions. Nature Phys 8, 539–543 (2012). https://doi.org/10.1038/nphys2318
NO Está depositada la versión postprint del artículo
NO Agence Nationale de la Recherche (France)
NO RTRA grant 'Supraspin'
NO Unión Europea 
NO Ministerio de Ciencia e Innovación (España)
DS Docta Complutense
RD 9 abr 2025