Concurrent transition of ferroelectric and magnetic ordering near room temperature

Strong spin-lattice coupling in condensed matter gives rise to intriguing physical phenomena such as colossal magnetoresistance and giant magnetoelectric effects. The phenomenological hallmark of such a strong spin-lattice coupling is the manifestation of a large anomaly in the crystal structure at the magnetic transition temperature. Here we report that the magnetic Néel temperature of the multiferroic compound BiFeO3 is suppressed to around room temperature by heteroepitaxial misfit strain. Remarkably, the ferroelectric state undergoes a first-order transition to another ferroelectric state simultaneously with the magnetic transition temperature. Our findings provide a unique example of a concurrent magnetic and ferroelectric transition at the same temperature among proper ferroelectrics, taking a step toward room temperature magnetoelectric applications. © 2011 Macmillan Publishers Limited. All rights reserved.open435

Measurement of the inclusive cross-section for the production of jets in association with a Z boson in proton-proton collisions at 8 TeV using the ATLAS detector

The inclusive cross-section for jet production in association with a Z boson decaying into an electron–positron pair is measured as a function of the transverse momentum and the absolute rapidity of jets using 19.9 fb −1 of s√=8 TeV proton–proton collision data collected with the ATLAS detector at the Large Hadron Collider. The measured Z + jets cross-section is unfolded to the particle level. The cross-section is compared with state-of-the-art Standard Model calculations, including the next-to-leading-order and next-to-next-to-leading-order perturbative QCD calculations, corrected for non-perturbative and QED radiation effects. The results of the measurements cover final-state jets with transverse momenta up to 1 TeV, and show good agreement with fixed-order calculations

Polarization-induced strain and wall roughness in ferroelectric 180° stripe domains probed by diffuse X-ray scattering

International audienc

Domain engineering and Polarization Rotation in Ferroelectric Tricolor Superlattices

International audienc

Polarization Rotation in Ferroelectric Tricolor PbTiO3 / SrTiO3 / PbZr0.2Ti0.8O3 Superlattices

National audienc

Domain engineering in Ferroelectric Tricolor Superlattices probed by X-ray diffraction

International audienc

Effects of thickness on the cation segregation in epitaxial (001) and (110) La2/3Ca1/3MnO3 thin films

Electron-energy-loss spectroscopy is used to map composition and electronic states in epitaxial La2/3Ca1/3MnO3 LCMO films of various thicknesses grown on SrTiO3 001 and 110 substrates. For relatively thick films 20 nm , epitaxial tensile strain in 001 films promotes a compositional La/Ca gradient across the film thickness, being the interface La rich, while the relaxed 110 films are chemically homogeneous. In contrast, much thinner 001 and 110 LCMO films display a different La/Ca distribution, being La rich at the free surface. The observed distinct thickness-dependent composition gradient behavior reflects a balance between strain-induced elastic energy minimization and kinetic effects during growth

Nanoscale electronic and structural properties in ferroelectric perovskite oxides from X-ray diffraction experiments

National audienc