A5078443504- Magnetic and transport properties of perovskites and related materials
- Electronic and Structural Properties of Oxides
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- Multiferroics and related materials
- Quantum and electron transport phenomena
- Rare-earth and actinide compounds
- Ferroelectric and Piezoelectric Materials
- Transition Metal Oxide Nanomaterials
- Plasmonic and Surface Plasmon Research
- Inorganic Chemistry and Materials
- Strong Light-Matter Interactions
- Physics of Superconductivity and Magnetism
- Advanced Memory and Neural Computing
- Magnetic Properties of Alloys
- Organic Electronics and Photovoltaics
- Thermal Radiation and Cooling Technologies
- Perovskite Materials and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Shape Memory Alloy Transformations
- X-ray Diffraction in Crystallography
- Conducting polymers and applications
- Magneto-Optical Properties and Applications
- Theoretical and Computational Physics
- Welding Techniques and Residual Stresses
University of Geneva
2014-2024
CIC nanoGUNE
2019-2024
Ayuntamiento de San Sebastián
2020
University of British Columbia
2014
Canadian Light Source (Canada)
2014
University of Genoa
2012
This review stands in the larger framework of functional materials by focussing on heterostructures rare-earth nickelates, described chemical formula RNiO3 where R is a trivalent = La, Pr, Nd, Sm, ..., Lu. Nickelates are characterized rich phase diagram structural and physical properties serve as benchmark for physics transitions correlated oxides electron–lattice coupling plays key role. Much recent interest nickelates concerns heterostructures, that single layers thin film, multilayers or...
Abstract The metal–insulator transition and the intriguing physical properties of rare-earth perovskite nickelates have attracted considerable attention in recent years. Nonetheless, a complete understanding these materials remains elusive. Here we combine X-ray absorption resonant inelastic scattering (RIXS) spectroscopies to resolve important aspects complex electronic structure nickelates, taking NdNiO 3 thin film as representative example. unusual coexistence bound continuum excitations...
The functional properties of oxide heterostructures ultimately rely on how the electronic and structural mismatches occurring at interfaces are accommodated by chosen materials combination. We discuss here LaMnO3/LaNiO3 heterostructures, which display an intrinsic interface asymmetry depending growth sequence. Using a variety synchrotron-based techniques, we show that degree intermixing monolayer scale allows interface-driven such as charge transfer induced magnetic moment in nickelate layer...
Nickelates are known for their metal to insulator transition (MIT) and an unusual magnetic ordering, occurring at T = TNéel. Here, we investigate thin films of SmNiO3 subjected different levels epitaxial strain. We find that the original bulk behavior (TNéel < TMI) is strongly affected by applying compressive strain films. For small strains, a regime where TNéel TMI achieved, paramagnetic insulating phase characteristic compound suppressed MIT becomes 1st order. Further increasing in-plane...
Abstract Nucleation processes of mixed-phase states are an intrinsic characteristic first-order phase transitions, typically related to local symmetry breaking. Direct observation emerging regions in materials showing a metal–insulator transition (MIT) offers unique opportunities uncover their driving mechanism. Using photoemission electron microscopy, we image the nanoscale formation and growth insulating domains across temperature-driven MIT NdNiO 3 epitaxial thin films. Heteroepitaxy is...
A marked conductivity enhancement is reported in 6–11 unit cell LaNiO 3 thin films. maximal also observed ab initio calculations for films of the same thickness. In agreement with results from state art scanning transmission electron microscopy, reveal a differentiated film structure comprising characteristic surface, interior, and heterointerface structures. Based on this observation, three‐element parallel conductor model considered leads to conclusion that cells, stems onset...
Bulk NdNiO_3 and thin films grown along the pseudocubic (001)_pc axis display a 1st order metal to insulator transition (MIT) together with N\'eel at T=200K. Here, we show that for NdNiO3 deposited on (111)_pc NdGaO_3 MIT occurs T=335K T=230 K. By comparing transport magnetic properties of layers substrates different symmetries lattice parameters, demonstrate particularly large tuning when epitaxy is realized surfaces. We attribute this effect specific matching conditions imposed direction...
Abstract Dimensionality is known to play an important role in many compounds for which ultrathin layers can behave very differently from the bulk. This especially true paramagnetic metal LaNiO 3 , become insulating and magnetic when only a few monolayers thick. We show here that induced antiferromagnetic order be stabilized [111] direction by interfacial coupling ferromagnet LaMnO used generate interlayer of nature depends on exact number monolayers. For 7-monolayer-thick /LaMnO...
Abstract Strong coupling between molecular vibrations and microcavity modes has been demonstrated to modify physical chemical properties of the material. Here, we study less explored lattice (phonons) modes. Embedding thin layers hexagonal boron nitride (hBN) into classical microcavities, demonstrate evolution from weak ultrastrong phonon-photon when hBN thickness is increased a few nanometers fully filled cavity. Remarkably, strong achieved for as 10 nm. Further, in cavities yields...
Using a combination of spectroscopic ellipsometry and DC transport measurements, we determine the temperature dependence optical conductivity ${\mathrm{NdNiO}}_{3}$ ${\mathrm{SmNiO}}_{3}$ films. The spectra show appearance characteristic two-peak structure in near-infrared when material passes from metal to insulator phase. Dynamical mean-field theory calculations confirm this allow us identify these spectral changes associated electronic structure. We demonstrate that insulating phase...
Strongly correlated quantum solids are characterized by an inherently granular electronic fabric, with spatial patterns that can span multiple length scales in proximity to a critical point. Here, we used resonant magnetic X-ray scattering nanoprobe sub-100 nm resolution directly visualize the texture of antiferromagnetic domains NdNiO$_3$. Surprisingly, our measurements revealed highly textured which is shown be robust and nonvolatile even after thermal erasure across its ordering...
A magnetic insulator is an ideal platform to propagate spin information by exploiting magnon currents. However, until now, most studies have focused on ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ (YIG) and a few other ferri- antiferromagnetic insulators, but not pure ferromagnets. In this study, we demonstrate that currents can in ferromagnetic insulating thin films of EuS. By performing both local nonlocal transport measurements 18-nm-thick EuS using Pt electrodes, detect arising...
Selective optical excitation of a substrate lattice can drive phase changes across hetero-interfaces. This phenomenon is non-equilibrium analogue static strain control in heterostructures and may lead to new applications optically controlled change devices. Here, we make use time-resolved non-resonant resonant x-ray diffraction clarify the underlying physics, separate different microscopic degrees freedom space time. We measure dynamics that charge disproportionation NdNiO3, when an...
Abstract The coupling of diverse degrees freedom opens the door to physical effects that go beyond each them individually, making multifunctionality a much sought‐after attribute for high‐performance devices. Here, multifunctional operation single‐layer p‐type organic device, displaying both spin transport and photovoltaic effect at room temperature on transparent substrate, is shown. generated photovoltage almost three times larger than applied bias device which facilitates modulation...
Strongly correlated perovskite oxides are a class of materials with fascinating intrinsic physical functionalities due to the interplay charge, spin, orbital ordering, and lattice degrees freedom. Among exotic phenomena arising from such an interplay, metal-insulator transitions (MITs) fundamentally still not fully understood large interest for novel nanoelectronics applications, as resistive switching-based memories neuromorphic computing devices. In particular, rare-earth nickelates...
We study the temperature dependence of optical conductivity rare-earth nickelate films varying composition and strain close to antiferromagnetic ordering temperature, TN. Two prominent peaks at 0.6 1.3 eV, which are characteristic insulating phase, display a small but significant increase in intensity when material passes from para- antiferromagnetic. This observation indicates presence positive feedback between (AF) bond disproportionation (BD) order. By analyzing near TN, using Landau-type...
We investigate the non-equilibrium insulator-metal transition driven in a SmNiO3 thin film by coherent optical excitation of LaAlO3 substrate lattice. By probing transient properties over broad frequency range (100 - 800 cm^-1), we analyze both time dependent metallic plasma and infrared phonon line shapes. show that light-induced phase has same carrier density as equilibrium phase. also report acts transducer only at earlier delays, vibrations are coherently. No long-lived structural...
The Spin Hall magnetoresistance (SMR) emerged as a reference tool to investigate the magnetic properties of materials with an all-electrical set-up. Its sensitivity magnetization thin films and surfaces may turn it into valuable technique characterize Van der Waals materials, which support long range order in atomically layers. However, realistic can be affected by defects disorder, result unexpected artifacts SMR, rather than sole appearance electrical noise. Here, we study SMR response...
Taking advantage of the large electron escape depth soft x-ray angle resolved photoemission spectroscopy, we report electronic structure measurements (111)-oriented [LaNiO3/LaMnO3] superlattices and LaNiO3 epitaxial films. For thin films, observe a 3D Fermi surface with an pocket at Brillouin zone center hole pockets vertices. Superlattices thick nickelate layers present similar structure. However, as thickness is reduced, become insulating. These heterostructures do not show marked...
Strongly correlated materials show unique solid-state phase transitions with rich nanoscale phenomenology that can be controlled by external stimuli. Particularly interesting is the case of light--matter interaction in proximity metal--insulator transition heteroepitaxial nickelates. In this work, we use near-infrared laser light high-intensity excitation regime to manipulate separation ${\mathrm{NdNiO}}_{3}$. By tuning intensity, reproducibly set coverage insulating nanodomains, which image...
Materials with strong electronic correlations host remarkable---and technologically relevant---phenomena such as magnetism, superconductivity, and metal-insulator transitions. Harnessing controlling these effects is a major challenge, on which key advances are being made through lattice strain engineering in thin films heterostructures, leveraging the complex interplay between structural degrees of freedom. Here we show that structure $\mathrm{La}\mathrm{Ni}{\mathrm{O}}_{3}$ can be tuned by...