Person: Sefrioui Khamali, Zouhair
Loading...
First Name
Zouhair
Last Name
Sefrioui Khamali
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Informática
Department
Física de Materiales
Area
Física Aplicada
Identifiers
12 results
Search Results
Now showing 1 - 10 of 12
Item Equal-spin Andreev reflection and long range coherent transport in hightemperature superconductor/half-metallic ferromagnet junctions(Nature Physics, 2012) Visani, Cristina; Sefrioui Khamali, Zouhair; Tornos Castillo, Javier; Villegas Hernández, Javier Eulogio; León Yebra, Carlos; Briatico, J.; Bibes, Manuel; Barthelemy, Agnes; Santamaría Sánchez-Barriga, JacoboConventional 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).Item All manganite tunnel junctions with interface induced barrier magnetism(Advanced Materials, 2010) Sefrioui Khamali, Zouhair; Rivera Calzada, Alberto Carlos; León Yebra, Carlos; Cuéllar Jiménez, Fabian Andrés; Santamaría Sánchez-Barriga, Jacobo; Barthélémy, A.; Sefrioui Khamali, ZouhairIn epitaxial heterostructures combining strongly correlated manganese oxides with antiferromagnetic-insulator or half-metallic character, a large interfacial moment is found and used to produce a spin-filter-like behavior in all-manganite tunnel junctions. The results suggest that after playing a key role in exchange-bias for spin-valves, uncompensated moments at engineered antiferromagnetic interfaces represent a novel route for generating highly spin-polarized currents with antiferromagnets.Item Signatures of a two‐dimensional ferromagnetic electron gas at the La0.7Sr0.3MnO3/SrTiO3 interface arising from orbital reconstruction(Advanced Materials, 2014) Nemes, Norbert Marcel; Calderón, María José; Beltrán Fínez, Juan Ignacio; Bruno, Flavio Yair; García‐Barriocanal, Javier; Sefrioui Khamali, Zouhair; León Yebra, Carlos; García Hernández, Mar; Muñoz, María Carmen; Brey, Luis; Santamaría Sánchez-Barriga, JacoboThe magnetoresistance of La0.7Sr0.3MnO3/SrTiO3 superlattices with magnetic field rotating out-of-plane shows unexpected peaks for in-plane fields. Resistivity calculations with spin–orbit coupling reveal that orbital reconstruction at the manganite interface leads to a 2D ferromagnetic electron gas coupled antiparallel to the manganite “bulk”. These orbital and magnetic reconstructions are supported by X-ray linear dichroism and ab initio calculations.- Project number: 224
Item Desarrollo de simuladores no virtuales en la docencia de la clínica equina(2020) López San Román, Francisco Javier; Manso Díaz, Gabriel; Villalba Orero, María; Jiménez Tabasco, Alberto; Sanz Dueñas, Javier; Santiago Llorente, Isabel; Sefrioui Khamali, Zouhair; Varela Del Arco, Marta; Velasco Matesanz, Laura; Martínez Sánchez, MercedesEl proyecto actual se ha centrado en el desarrollo de modelos no virtuales. La adquisición de habilidades prácticas sigue diferentes pasos en la curva de aprendizaje y, para ello, es necesario partir de un conocimiento de las bases teóricas y observar previamente el procedimiento. Sin embargo, el alumno debe de llevar a cabo el procedimiento por si mismo. En la actualidad esto se realiza con cadáveres y animales vivos, lo cual está limitado por el cada vez más complicado acceso a los primeros y la estricta normativa vigente sobre bienestar animal. Por esta razón, hemos pretendido crear simuladores que suplan las limitaciones actuales. De tal manera, hemos comenzado con la creación de un modelo de artroscopia equina con la articulación radiocarpiana que facilite, por un lado, el entendimiento de la anatomía artroscopia de las articulaciones equinas y, por otro lado, el desarrollo de sus habilidades prácticas. - Project number: PIMCD355/23-24
Item Métodos innovativos en la docencia en el ámbito de electromagnetismo usando la herramienta Wooclap(2024) Biskup Zaja, Nevenko; Nemes, Norbert Marcel; León Yebra, Carlos; Santamaría Sánchez-Barriga, Jacobo; Sánchez Santolino, Gabriel; Sefrioui Khamali, Zouhair; Schmidt, Rainer; Varela Del Arco, María; Azcondo Sánchez, M. Teresa; Rivera Calzada, Alberto Carlos; Scimemi, Ignacio; Barbero Velasco, Isabel; Zamora Castro, Victor; Ternero Villar, Isabel; Romero de Paz, Julio Item Large magnetoresistance of isolated domain walls in La_(0.7)Sr(0.3)MnO_3 nanowires(Advanced Materials, 2023) Orfila Rodríguez, Gloria; Sanchez-Manzano, David; Arora, Ashima; Cuéllar Jiménez, Fabian Andrés; Ruiz Gómez, Sandra; Rodriguez-Corvillo, Sara; López, Sandra; Peralta, Andrea; Carreira, Santiago J.; Gallego, Fernando; Tornos Castillo, Javier; Rouco Gómez, Víctor; Riquelme, Juan J.; Munuera, Carmen; Mompean, Federico J.; Garcia-Hernandez, Mar; Sefrioui Khamali, Zouhair; Villegas Hernández, Javier Eulogio; Pérez García, Lucas; Rivera Calzada, Alberto Carlos; León Yebra, Carlos; Valencia, Sergio; Santamaría Sánchez-Barriga, JacoboGeneration, manipulation, and sensing of magnetic domain walls are cornerstones in the design of efficient spintronic devices. Half-metals are amenable for this purpose as large low field magnetoresistance signals can be expected from spin accumulation at spin textures. Among half metals, La1−xSrxMnO3 (LSMO) manganites are considered as promising candidates for their robust half-metallic ground state, Curie temperature above room temperature (Tc = 360 K, for x = 1/3), and chemical stability. Yet domain wall magnetoresistance is poorly understood, with large discrepancies in the reported values and conflicting interpretation of experimental data due to the entanglement of various source of magnetoresistance, namely, spin accumulation, anisotropic magnetoresistance, and colossal magnetoresistance. In this work, the domain wall magnetoresistance is measured in LSMO cross-shape nanowires with single-domain walls nucleated across the current path. Magnetoresistance values above 10% are found to be originating at the spin accumulation caused by the mistracking effect of the spin texture of the domain wall by the conduction electrons. Fundamentally, this result shows the importance on non-adiabatic processes at spin textures despite the strong Hund coupling to the localized t2g electrons of the manganite. These large magnetoresistance values are high enough for encoding and reading magnetic bits in future oxide spintronic sensors.Item ‘‘Charge Leakage’’ at LaMnO_3/SrTiO_3 Interfaces(Advanced Materials, 2010) Garcia Barriocanal, Javier; Bruno, Flavio Yair; Rivera Calzada, Alberto Carlos; Sefrioui Khamali, Zouhair; Nemes, Norbert Marcel; Garcia Hernández, Mar; Rubio Zuazo, Juan; Castro, German R.; Varela Del Arco, María; Pennycook, J.; León Yebra, Carlos; Santamaría Sánchez-Barriga, JacoboDirect evidence for charge leakage at the interface of epitaxial SrTiO3/LaMnO3 superlattices with atomically sharp interfaces is provided. The direction of charge leakage can be reversed by changing the LMO/STO thickness ratio. This result will be important for the understanding of some of the reported limitations of oxide devices involving manganite/titanate interfaces.Item Ferroionic inversion of spin polarization in a spin-memristor(APL materials, 2021) Rouco Gómez, Víctor; Gallego Toledo, Fernando; Hernández Martín, D.; Sánchez Manzano, David; Tornos Castillo, Javier; Beltrán Fínez, Juan Ignacio; Cabero Piris, Mariona; Cuéllar Jiménez, Fabian Andrés; Arias Serna, Diego; Sánchez Santolino, Gabriel; Mompean, F. J.; García Hernández, M.; Rivera Calzada, Alberto Carlos; Muñoz, María del Carmen; León Yebra, Carlos; Sefrioui Khamali, Zouhair; Santamaría Sánchez-Barriga, JacoboMagnetoelectric coupling in artificial multiferroic interfaces can be drastically affected by the switching of oxygen vacancies and by the inversion of the ferroelectric polarization. Disentangling both effects is of major importance toward exploiting these effects in practical spintronic or spinorbitronic devices. We report on the independent control of ferroelectric and oxygen vacancy switching in multiferroic tunnel junctions with a La_(0.7)Sr_(0.3)MnO_3 bottom electrode, a BaTiO_3 ferroelectric barrier, and a Ni top electrode. We show that the concurrence of interface oxidation and ferroelectric switching allows for the controlled inversion of the interface spin polarization. Moreover, we show the possibility of a spin-memristor where the controlled oxidation of the interface allows for a continuum of memresistance states in the tunneling magnetoresistance. These results signal interesting new avenues toward neuromorphic devices where, as in practical neurons, the electronic response is controlled by electrochemical degrees of freedom.Item Resonant electron tunnelling assisted by charged domain walls in multiferroic tunnel junctions(Nature Nanotechnology, 2017) Sánchez Santolino, Gabriel; Tornos Castillo, Javier; Hernandez-Martin, David; Beltrán Fínez, Juan Ignacio; Munuera, Carmen; Cabero Piris, Mariona; Perez-Muñoz, Ana; Ricote, Jesús; Mompean, Federico; Garcia-Hernandez, Mar; Sefrioui Khamali, Zouhair; León Yebra, Carlos; Pennycook, Steve, J.; Muñoz, María Carmen; Varela Del Arco, María; Santamaría Sánchez-Barriga, JacoboThe peculiar features of domain walls observed in ferroelectrics make them promising active elements for next-generation non-volatile memories, logic gates and energy-harvesting devices. Although extensive research activity has been devoted recently to making full use of this technological potential, concrete realizations of working nanodevices exploiting these functional properties are yet to be demonstrated. Here, we fabricate a multiferroic tunnel junction based on ferromagnetic La0.7Sr0.3MnO3 electrodes separated by an ultrathin ferroelectric BaTiO3 tunnel barrier, where a head-to-head domain wall is constrained. An electron gas stabilized by oxygen vacancies is confined within the domain wall, displaying discrete quantum-well energy levels. These states assist resonant electron tunnelling processes across the barrier, leading to strong quantum oscillations of the electrical conductance.Item Interface magnetism in La0.7Ca0.3MnO3/PrBa2Cu3O7 epitaxial heterostructures(Physica Status Solidi A, 2018) Cuéllar Jiménez, Fabian Andrés; Hernández Martín, David; Tornos Castillo, Javier; Gallego Toledo, Fernando; Orfila Rodríguez, Gloria; Rivera Calzada, Alberto Carlos; Sefrioui Khamali, Zouhair; León Yebra, Carlos; Santamaría Sánchez-Barriga, JacoboAll oxide magnetic tunnel junctions based on epitaxial La0.7Ca0.3MnO3 (LCMO)(8nm)/PrBa2Cu3O7 (PBCO) (3-8nm)/LCMO(25-50nm) heterostructures grown on (100) SrTiO3 are examined. Manganite electrodes show large (bulk-like) magnetic moments and exhibit different magnetic anisotropies with different easy axes directions. A form of low dimensional magnetism is induced at the interfaces by the superexchange interaction across the reconstructed bonds. It acts as an exchange spring, driving ferromagnetic coupling between the electrodes. Resistance versus magnetic field loops demonstrate that the interfacial coupling strength depends on electric field through its effect on electronic reconstruction and orbital hierarchy at the interface. The electrically controlled magnetic coupling between the magnetic moments of the electrodes signals a new path toward low dissipation spintronics.