In: Physical Review Letters, 2013, vol. 111, no. 3, p. 037201
Single phase and strained LuMnO₃ thin films are discovered to display coexisting ferromagnetic and antiferromagnetic orders. A large moment ferromagnetism (≈1μB), which is absent in bulk samples, is shown to display a magnetic moment distribution that is peaked at the highly strained substrate-film interface. We further show that the strain-induced ferromagnetism and the...
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In: Physical Review B - Condensed Matter and Materials Physics, 2013, vol. 87, no. 11, p. 115105
Using polarized neutron reflectometry (PNR) we have investigated a [YBa₂Cu₃O₇(10 nm)/La2/3Ca1/3MnO₃(9 nm)]₁₀ (YBCO/LCMO) superlattice grown by pulsed laser deposition on a La0.3Sr0.7Al0.65Ta0.35O₃ (LSAT) substrate. Due to the high structural quality of the superlattice and the substrate, the specular reflectivity...
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In: Physical Review B - Condensed Matter and Materials Physics, 2012, vol. 86, no. 01, p. 014408
Artificial multiferroic systems, in which novel properties can emerge from elastic coupling between piezoelectric and magnetostrictive phases, are a promising route to obtain significant room-temperature magnetoelectric coupling at the nanoscale. In this work, we have used element-specific soft x-ray photoemission electron microscopy to spatially resolve the effects of ferroelectric BaTiO₃ on...
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In: Physical Review B - Condensed matter and materials physics, 2012, vol. 85, no. 5, p. 054514
Heteroepitaxial superlattices of [YBa₂Cu₃O₇(n)/La0.67Ca0.33MnO₃(m)]x (YBCO/LCMO), where n and m are the number of YBCO and LCMO monolayers and x the number of bilayer repetitions, have been grown with pulsed laser deposition on NdGaO₃ (110) and Sr0.7La0.3Al0.65Ta0.35O₃ (001). These substrates are well lattice...
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In: Physical Review B - Condensed matter and materials physics, 2012, vol. 85, no. 2, p. 024505
We present a low-energy muon-spin-rotation study of the magnetic and superconducting properties of YBa₂Cu₃O7−δ/PrBa₂Cu₃O7−δ trilayer and bilayer heterostructures. By determining the magnetic-field profiles throughout these structures, we show that a finite superfluid density can be induced in otherwise semiconducting PrBa₂Cu₃O7−δ layers...
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In: Science, 2011, vol. 332, no. 6032, p. 937-940
The competition between collective quantum phases in materials with strongly correlated electrons depends sensitively on the dimensionality of the electron system, which is difficult to control by standard solid-state chemistry. We have fabricated superlattices of the paramagnetic metal lanthanum nickelate (LaNiO₃) and the wide-gap insulator lanthanum aluminate (LaAlO₃) with atomically...
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In: Nature Materials, 2011, vol. 10, p. 39–44
Spintronics has shown a remarkable and rapid development, for example from the initial discovery of giant magnetoresistance in spin valves (Baibich, M. N. et al. Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. Phys. Rev. Lett. 61, 2472–2475, 1988) to their ubiquity in hard-disk read heads in a relatively short time. However, the ability to fully harness electron spin as...
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In: Physical Review Letters, 2011, vol. 106, no. 4, p. 047006
We show that a multilayer analysis of the infrared c-axis response of RBa₂Cu₃O7-δ (R=Y,Gd,Eu) provides important new information about the anomalous normal-state properties of underdoped cuprate high temperature superconductors. In addition to competing correlations which give rise to a pseudogap that depletes the low-energy electronic states below...
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In: Journal of Physics: Condensed Matter, 2011, vol. 23, no. 6, p. 065102
Magnetic properties of particles are generally determined from randomly oriented ensembles and the influence of the particle orientation on the magnetic response is neglected. Here, we report on the magnetic characterization of anisotropic spindle- type hematite particles. The easy axis of magnetization is within the basal plane of hematite, which is oriented perpendicular to the spindle axis....
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In: The European Physical Journal - Special Topics, 2010, vol. 188, no. 1, p. 73-88
With the technique of infrared ellipsometry we performed a detailed study of the temperature- and doping dependence of the c-axis response of a series of YBa₂Cu₃O7−δ single crystals. In particular, we explored the anomalous electronic properties at temperatures above the macroscopic superconducting transition temperature, T c, whose conflicting...
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