In: Physical Review Materials, 2019, vol. 3, no. 8, p. 084801
We studied how the electronic, superconducting, and magnetic properties of YBa2Cu3O7/Nd1−x(Ca1−ySry )xMnO3 multilayers depend on the tolerance factor and the hole doping of the manganite. In particular, we investigated the granular superconducting state and the related magnetic-field-driven insulator-to- superconductor transition that was previously discovered in corresponding multilayers...
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In: Communications Physics, 2018, vol. 1, no. 1, p. 45
The observation of a charge density wave in the underdoped cuprate high Tc superconductors (Cu-CDW) raised a debate about its relationship with superconductivity. In bulk YBa2Cu3O7−δ the Cu-CDW is incipient and mainly pinned by defects. Nevertheless, a large magnetic field can induce a true long-range Cu- CDW order as it suppresses superconductivity. An enhanced Cu-CDW order was also ...
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In: Applied Physics Letters, 2017, vol. 111, no. 23, p. 232102
Using in situ grazing-incidence x-ray scattering, we have measured the diffuse scattering from islands that form during layer-by-layer growth of GaN by metal-organic vapor phase epitaxy on the (101⎯⎯0)(101¯0)(101¯0) m-plane surface. The diffuse scattering is extended in the (0001)(0001)(0001) in-plane direction in reciprocal space, indicating a strong anisotropy with islands elongated...
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In: Journal of Physics: Condensed Matter, 2017, vol. 29, no. 49, p. 495601
We studied the structural, magnetic and electronic properties of ${\rm SrFeO}_{3- \delta}$ (SFO) thin films and ${\rm SrFeO}_{3-\delta}$ /${\rm La}_{2/3}$ ${\rm Ca}_{1/3}$ MnO3 (LCMO) superlattices that have been grown with pulsed laser deposition (PLD) on ${\rm La}_{0.3}$ ${\rm Sr}_{0.7}$ ${\rm Al}_{0.65}$ ${\rm Ta}_{0.35}$ ${\rm O}_{3}$ (LSAT) substrates. X-ray reflectometry and scanning ...
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In: Physical Review B, 2016, vol. 94, no. 18, p. 180503
We show that in Pr0.5La0.2Ca0.3MnO3/YBa2Cu3O7 (PLCMO/YBCO) multilayers the low temperature state of YBCO is very resistive and resembles that of a granular superconductor or a frustrated Josephson-junction network. Notably, a coherent superconducting response can be restored with a large magnetic field which also suppresses the charge-orbital order in PLCMO. This coincidence suggests that the...
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In: Physical Review B, 2016, vol. 93, no. 20, p. 205131
With x-ray absorption spectroscopy and polarized neutron reflectometry we studied how the magnetic proximity effect at the interface between the cuprate high-TC superconductor YBa2Cu3O7 (YBCO) and the ferromagnet La2/3Ca1/3MnO3 (LCMO) is related to the electronic and magnetic properties of the LCMO layers. In particular, we explored how the magnitude of the ferromagnetic Cu moment on the YBCO...
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In: Physical Review X, 2016, vol. 6, no. 1, p. 11014
Spatial confinement induces microscopic ordering of fluids, which in turn alters many of their dynamic and thermodynamic properties. However, the isothermal compressibility has hitherto been largely overlooked in the literature, despite its obvious connection to the underlying microscopic structure and density fluctuations in confined geometries. Here, we address this issue by probing density...
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In: Soft Matter, 2010, vol. 6, no. 18, p. 4536-4539
We have applied holographic X-ray diffraction from fluid-filled channel arrays for model-independent density reconstruction of spherical AOT/water/isooctane reverse micelles (average diameter σ***Missing image substitution***12–13 nm) confined between planar surfaces. We find the confinement-induced ordering of the reverse micelles to strongly depend on the surface potential of the...
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In: Journal of Synchrotron Radiation, 2010, vol. 17, no. 4, p. 465-472
An X-ray reflectivity theory on the determination of the density profile of a molecular liquid under nanometre confinement is presented. The confinement geometry acts like an X-ray interferometer, which consists of two opposing atomically flat single-crystal mica membranes with an intervening thin liquid film of variable thickness. The X-rays reflected from the parallel crystal planes (of known...
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In: Journal of Physics: Condensed Matter, 2010, vol. 22, no. 23, p. 235102
Ultrathin (<12 nm) films of tetrakis(trimethyl)siloxysilane (TTMSS) have been confined by atomically flat mica membranes in the presence and absence of applied normal forces. When applying normal forces, discrete film thickness transitions occur, each involving the expulsion of TTMSS molecules. Using optical interferometry we have measured the step size associated with a film thickness transition...
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