In: Physical Review B, 2008, vol. 78, no. 13, p. 134111
We investigated with synchrotron x-ray diffraction and reflectometry the formation of structural domains in the near-surface region of single crystalline SrTiO₃ (001) substrates with Y0.6Pr0.4Ba₂Cu₃O₇/La2/3Ca1/3MnO₃ superlattices grown on top. We find that the antiferrodistortive cubic to tetragonal transition, which occurs at...
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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 B, 2014, vol. 90, no. 20, p. 205135
With x-ray absorption spectroscopy we investigated the orbital reconstruction and the induced ferromagnetic moment of the interfacial Cu atoms in YBa2Cu3O7/La2/3Ca1/3MnO3 (YBCO/LCMO) and La2−xSrxCuO4/La2/3Ca1/3MnO3 (LSCO/LCMO) multilayers. We demonstrate that these electronic and magnetic proximity effects are coupled and are common to these cuprate/manganite multilayers. Moreover, we show that...
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In: Nature Materials, 2012, vol. 11, p. 497–501
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In: Physical Review Letters, 2010, vol. 104, no. 3, p. 036401
We report spectroscopic ellipsometry measurements of the anisotropy of the interband transitions parallel and perpendicular to the planes of (LaTiO₃)n(LaAlO₃)5 multilayers with n=1–3. These provide direct information about the electronic structure of the two-dimensional (2D) 3d¹ state of the Ti ions. In combination with local density approximation, including a Hubbard U calculation, we...
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In: EPJ Web of Conferences, 2013, vol. 41, p. 03012
We trace the ultrafast dynamics of the spin density wave gap of the pnictide system BaFe2As2 probing resonantly with broadband multi-terahertz pulses. The photoexcitation in the low-temperature ground state leads to a fast suppression of the spin order followed by a slower recovery process. Surprisingly, in the normal state, we observe periodic oscillations of the spin density wave feature at a...
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In: Physical Review Letters, 2021, vol. 126, no. 15, p. 157401
Terahertz vortex beams with different superposition of the orbital angular momentum $l={\pm}1$, ${\pm}2$, ${\pm}3$, and ${\pm}4$ and spin angular momentum ${\sigma}={\pm}1$ were used to study antiferromagnetic (AFM) resonances in TbFe$_3$(BO$_3$)$_4$ and Ni$_3$TeO$_6$ single crystals. In both materials we observed a strong vortex beam dichroism for the AFM resonances that are split in ...
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In: Physical Review Letters, 2019, vol. 122, no. 23, p. 237401
Circularly polarized light with spin angular momentum is one of the most valuable probes of magnetism. We demonstrate that light beams with orbital angular momentum (OAM), or vortex beams, can also couple to magnetism exhibiting dichroisms in a magnetized medium. Resonant optical absorption in a ferrimagnetic crystal depends strongly on both the handedness of the vortex and the direction of...
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In: Applied Physics Letters, 2016, vol. 108, no. 5, p. 052901
We present a combined study with time-domain terahertz and conventional far-infrared ellipsometry of the temperature dependent optical response of SrTiO₃thin films (82 and 8.5 nm) that are grown by pulsed-laser deposition on (La0.3Sr0.7) (Al0.65Ta0.35)O₃ (LSAT) substrates. We demonstrate that terahertz ellipsometry is very sensitive to the optical...
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In: Nature Physics, 2019, vol. 15, no. 4, p. 387–392
Direct manipulation of the atomic lattice using intense long-wavelength laser pulses has become a viable approach to create new states of matter in complex materials. Conventionally, a high-frequency vibrational mode is driven resonantly by a mid- infrared laser pulse and the lattice structure is modified through indirect coupling of this infrared-active phonon to other, lower-frequency...
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