Magnetic Phase Diagram of van der Waals Antiferromagnet TbTe3

Terbium tritelluride, TbTe3, orders antiferromagnetically in three steps at TN1 = 6.7 K, TN2 = 5.7 K, and TN3 = 5.4 K, preceded by a correlation hump in magnetic susceptibility at T* ~8 K. Combining thermodynamic, i.e., specific heat Cp and magnetization M, and transport, i.e., resistance R, measurements we established the boundaries of two commensurate and one charge density wave modulated phases in a magnetic field oriented along principal crystallographic axes. Based on these measurements, the magnetic phase diagrams of TbTe3 at H‖a, H‖b and H‖c were constructed

The effect of the cladding refractive index on an optical fiber evanescent-wave sensor

Evanescent field interactions can be used to provide a variety of sensing modalities in optical fibers with a modified cladding. However, the evanescent field interaction with the surrounding environment is strongly dependent on the refractive index of the modified cladding region. This can lead to difficulties due to dispersion in the refractive index, particularly in fluorescence based sensors where the excitation and emission wavelengths are separated. Here, a broadband supercontinuum light source has been used to characterize the refractive index dependence of the sensor response over a wide wavelength range. The critical effect of the cladding refractive index on the performance of an optical fiber evanescent wave sensor is demonstrated for both amplitude and wavelength modulated situations. In principle, this approach can be used to predict the performance of the sensor over the full wavelength range of the broadband source. The results also suggest that residues from the original cladding of the fiber cause an intrinsic loss, which reduces the sensitivity at low levels of extrinsic absorption. The integrity of the interface between the core and the modified cladding is therefore an important parameter to be addressed in practical sensing applications

Magnetic Phase Diagram of van der Waals Antiferromagnet TbTe₃

Terbium tritelluride, TbTe3, orders antiferromagnetically in three steps at TN1 = 6.7 K, TN2 = 5.7 K, and TN3 = 5.4 K, preceded by a correlation hump in magnetic susceptibility at T* ~8 K. Combining thermodynamic, i.e., specific heat Cp and magnetization M, and transport, i.e., resistance R, measurements we established the boundaries of two commensurate and one charge density wave modulated phases in a magnetic field oriented along principal crystallographic axes. Based on these measurements, the magnetic phase diagrams of TbTe3 at H‖a, H‖b and H‖c were constructed

Bilayer splitting versus Fermi-surface warping as an origin of slow oscillations of in-plane magnetoresistance in rare-earth tritellurides

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La courbure d'une onde de densité de charge observée par une source Xfel utilisée comme une lentille électronique pour les rayons X

Ultrafast X-ray diffraction by the LCLS free-electron laser has been used to probe Charge Density Wave (CDW) systems under applied external currents. At sufficiently low currents, CDW wavefronts bend in the direction transverse to the 2kF wave vector. We show that this shear effect has the ability to focus or defocus hard X-ray beams, depending of the current direction, making it an electronic lens of a new kind, tunable at will from the Fraunhofer to the Fresnel regime. The effect is interpreted using the fractional Fourier transform showing how the macroscopic curvature of a nanometric modulation can be beneficially used to modify the propagation of X-ray beams