Ultrafast Photoresponse of Superconductor/Ferromagnet Nano-Layered Hybrids

Interfacial effects revealed by ultrafast relaxation dynamics inBiFeO3/YBa2Cu3O7bilayers

“…2,3 Complex oxide heterostructures of superconductors have been studied extensively in recent years. [4][5][6] Bringing different transition metal cations with their localized d-electron physics and interacting charge, spin, and lattice degrees of freedom, into contact in a tunable crystalline environment, activates new electronic properties not observable in bulk compounds. Epitaxial strain mismatch, atomic coordination frustration, ordered spin and orbital states, charge flow across the interface, chemical frustration, and competing phases placed in close proximity conspire for new phases to emerge.…”

“…It has proven to be a useful time-domain tool to probe dynamics of complex structures 5,[7][8][9][10] and coexisting 11 /competing 12,13 phases in superconductors. Thus ultrafast optical spectroscopy is well suited to study competing interactions in heterostructures containing HTSCs.…”

“…For example, in superconductorferromagnet (S/F) bilayers such as Nb/NiCu, NbN/NiCu and YBCO/Au/NiCu, the initial fast relaxation, which involves Cooper-pair breaking and quasiparticle (QP) recombination, is always faster in S/F bilayers than in pure superconductors, but only in the superconducting state. 5 The faster relaxation was attributed to the presence of suppressed superconductivity at the pump spot, called the hotspot, whose size is of the order of the superconducting coherence length ξ. These hotspots, where the superconducting energy gap ∆ is reduced, act as energy traps that cause faster QP recombination and hence speed up the relaxation process.…”

Interfacial effects revealed by ultrafast relaxation dynamics in BiFeO$_{3}$/YBa$_{2}$Cu$_{3}$O$_{7}$ bilayers

“…Time-resolved pump-probe ultrafast optical spectroscopy has been widely used in probing the relaxation dynamics of photoexcited quasiparticles in correlated electron systems, and in particular, high-temperature superconductors (HTSCs). It has proven to be a useful time-domain tool to probe dynamics of complex structures 5,[7][8][9][10] and coexisting 11 /competing 12,13 phases in superconductors. Thus ultrafast optical spectroscopy is well suited to study competing interactions in heterostructures containing HTSCs.…”

Infrared Photo-Response of Fe-Shunted Ba-122 Thin Film Microstructures

“…This allows further decrease of film thickness that is important for development of devices for different cryogenic applications like fast and sensitive bolometer detectors for electromagnetic radiation. Moreover, ferromagnetic/superconductor bi-layers of conventional and high-T c superconductors demonstrate a faster photo response in respect to detectors made from bare superconducting films [8].…”