We report herein on the magneto-chiral dichroism (MChD), investigated through near infrared light absorption, of a chiral nanomagnet showing room temperature magneto-electric coupling. The MChD signal associated with the Yb center is driven by the magnetic dipole allowed character of the F ← F electronic transition (|Δ| = 1). Magnetic field and temperature dependence studies reveal an MChD signal that follows the material magnetization and persists at room temperature.
View Article and Find Full Text PDFHere we report on the Magneto-Chiral Dichroism (MChD) detected through visible and near-infrared light absorption of two enantiomeric pairs of Er and Tm chiral complexes featuring a propeller-like molecular structure. The magnetic properties show typical features of isolated paramagnetic ions associated with I and H ground state terms. MChD spectroscopy shows high g dissymmetry factors of ca.
View Article and Find Full Text PDFMagnetic materials are widely used for many technologies in energy, health, transportation, computation, and data storage. For the latter, the readout of the magnetic state of a medium is crucial. Optical readout based on the magneto-optical Faraday effect was commercialized but soon abandoned because of the need for a complex circular polarization-sensitive readout.
View Article and Find Full Text PDFHere we report on the strong magneto-chiral dichroism (MChD) detected through visible and near-infrared light absorption up to 5.0 T on {ErNi} metal clusters obtained by reaction of enantiopure chiral ligands and Ni and Er precursors. Single-crystal diffraction analysis reveals that these compounds are 34 heterometallic clusters, showing helical chirality.
View Article and Find Full Text PDFJ Phys Chem Lett
November 2023
The combination of chirality and magnetism has steadily grown over the past decennia into an area of intense research that evolves around two distinct manifestations and in two nonoverlapping communities: electrical magnetochiral anisotropy (eMChA) and chirality-induced spin-selectivity (CISS). Here, we discuss the similarities and differences of these two effects. Whereas the original CISS reports suggest an intimate relation with eMChA, magnetoresistance (MR) results on two-terminal chiral devices attributed to CISS have symmetry properties that are different from those of eMChA.
View Article and Find Full Text PDFHere we report magneto-chiral dichroism (MChD) detected through visible and near-infrared light absorption of a chiral dysprosium(III) coordination polymer. The two enantiomers of [Dy(H6(py))(hfac)] [H6(py) = 2,15-bis(4-pyridyl)ethynylcarbo[6]helicene; hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate], where the chirality is provided by a functionalized helicene ligand, were structurally, spectroscopically, and magnetically investigated. Magnetic measurements reveal a slow relaxation of the magnetization, with differences between enantiopure and racemic systems rationalized on the basis of theoretical calculations.
View Article and Find Full Text PDFBecause the combination of chiral and magnetic properties is becoming more and more attractive for magneto-chiral phenomena, we here aim at exploring the induction of chirality to achiral magnetic molecules as a strategy for the preparation of magneto-chiral objects. To this end, we have associated free base- and metallo-porphyrins with silica nano helices, using a variety of elaboration methods, and have studied them mainly by electronic natural circular dichroism (NCD) and magnetic circular dichroism (MCD) spectroscopies. While electrostatic or covalent surface grafting uniformly yielded very low induced CD (ICD) for the four assayed porphyrins, a moderate response was observed when the porphyrins were incorporated into the interior of the double-walled helices, likely due to the association of the molecules with the chirally-organized gemini surfactant.
View Article and Find Full Text PDFWe propose a novel method for enantioselective electron paramagnetic resonance (EPR) spectroscopy based on magneto-chiral anisotropy. We elaborate a theoretical model to estimate the strength of this effect and propose a dedicated interferometer setup for its experimental observation.
View Article and Find Full Text PDFThe combination of physical properties sensitive to molecular chirality in a single system allows the observation of fascinating phenomena such as magneto-chiral dichroism (MChD) and circularly polarized luminescence (CPL) having potential applications for optical data readout and display technology. Homochiral monodimensional coordination polymers of Yb were designed from a 2,15-bis-ethynyl-hexahelicenic scaffold decorated with two terminal 4-pyridyl units. Thanks to the coordination of the chiral organic chromophore to Yb(hfac) units (hfac =1,1,1,5,5,5-hexafluoroacetylaconate), efficient NIR-CPL activity is observed.
View Article and Find Full Text PDFThe combination of chirality and magnetism has steadily grown over the last decennia into an area of intense research. Magnetochiral anisotropy, chirality-induced spin-selectivity and helimagnetism are the most prominent phenomena resulting from this combination, touching different systems like topological (semi-)metals and insulators, quantum magnets, type II multiferroics and enantio-selective synthesis. As an extension to this area, we argue, based on symmetry arguments, that magnetochiral anisotropy will manifest itself in the displacement current in chiral dielectrics in a magnetic field.
View Article and Find Full Text PDFHere, we report the molecular self-assembly of hydroxido-bridged {LnNi} ((Ln = Dy, Y) metal clusters by the reaction of enantiopure chiral ligands, namely, (/)-(2-hydroxy-3-methoxybenzyl)-serine), with Ni and Ln precursors. Single-crystal diffraction analysis reveals that these compounds are isostructural sandwich-like 3d-4f heterometallic clusters showing helical chirality. Direct current magnetic measurements on {DyNi} indicates ferromagnetic coupling between Dy and Ni centers, whereas those on {YNi} denote that the Ni centers are antiferromagnetically coupled and/or magnetically anisotropic.
View Article and Find Full Text PDFMultilayered cuprates possess not only the highest superconducting temperature transition but also offer a unique platform to study disorder-free CuO planes and the interplay between competing orders with superconductivity. Here, we study the underdoped trilayer cuprate HgBaCaCuO and we report quantum oscillation and Hall effect measurements in magnetic field up to 88 T. A careful analysis of the complex spectra of quantum oscillations strongly supports the coexistence of an antiferromagnetic order in the inner plane and a charge order in the outer planes.
View Article and Find Full Text PDFThe interplay between chirality and magnetic fields gives rise to a cross effect referred to as magneto-chiral anisotropy (MChA), which can manifest itself in different physical properties of chiral magnetized materials. The first experimental demonstration of MChA was by optical means with visible light. Further optical manifestations of MChA have been evidenced across most of the electromagnetic spectrum, from terahertz to X-rays.
View Article and Find Full Text PDFThe connection between chirality and electromagnetism has attracted much attention through the recent history of science, allowing the discovery of crucial nonreciprocal optical phenomena within the context of fundamental interactions between matter and light. A major phenomenon within this family is the so-called Faraday chiral anisotropy, the long-predicted but yet unobserved effect which arises due to the correlated coaction of both natural and magnetically induced optical activities at concurring wavelengths in chiral systems. Here, we report on the detection of the elusive anisotropic Faraday chiral phenomenon and demonstrate its enantioselectivity.
View Article and Find Full Text PDFMagnetochiral dichroism (MChD), a fascinating manifestation of the light-matter interaction characteristic for chiral systems under magnetic fields, has become a well-established optical phenomenon reported for many different materials. However, its interpretation remains essentially phenomenological and qualitative, because the existing microscopic theory has not been quantitatively confirmed by confronting calculations based on this theory with experimental data. Here, we report the experimental low-temperature MChD spectra of two archetypal chiral paramagnetic crystals taken as model systems, tris(1,2-diaminoethane)nickel(II) and cobalt(II) nitrate, for light propagating parallel or perpendicular to the axis of the crystals, and the calculation of the MChD spectra for the Ni(II) derivative by state-of-the-art quantum chemical calculations.
View Article and Find Full Text PDFHere we report the first experimental observation of magneto-chiral dichroism (MChD) detected through light absorption in an enantiopure lanthanide complex. The and enantiomers of [Yb(()-)()] (X = , ; = 3-(2-pyridyl)-4-aza[6]-helicene; = 1,1,1,5,5,5-hexafluoroacetylacetonate), where the chirality is held by the helicene-based ligand, were studied in the near-infrared spectral window. When irradiated with unpolarized light in a magnetic field, these chiral complexes exhibit a strong MChD signal ( ca.
View Article and Find Full Text PDFPhys Rev Lett
September 2020
We present a new optical effect that exchanges angular momentum between light and matter. The matter consists of an optically thick spherical, rigid agglomerate of magneto-optical scatterers placed in a homogeneous magnetic field. The light comes from an unpolarized, coherent central light source.
View Article and Find Full Text PDFMagnetochiral dichroism (MChD) is a nonreciprocal manifestation of light-matter interaction that can be observed in chiral magnetized systems. It features a differential absorption of unpolarized light depending on the relative orientation of the magnetic field and the light wavevector and on the absolute configuration of the system. The relevance of this effect for optical readout of magnetic data calls for a complete understanding of the microscopic parameters driving MChD with an easy-accessible and nondamaging light source, such as visible light.
View Article and Find Full Text PDFMagneto-chiral dichroism (MChD) is a non-reciprocal manifestation of light-matter interaction that can be observed in chiral systems possessing a magnetization, either spontaneous or induced by an external magnetic field. It features a differential absorption or emission of unpolarized light that depends on the relative orientation of the magnetization with respect to the direction of the light propagation vector and on the absolute configuration of the system. Molecular chemistry is the best-suited route towards systems combining chirality and magnetism.
View Article and Find Full Text PDFHere we report on magneto-chiral dichroism (MChD) detected with visible light on the chiral Prussian Blue Analogue [Mn(-H)(HO)][Cr(CN)]·HO (X = , ; = 1,2-propanediamine). Single crystals suitable for magneto-optical measurements were grown starting from enantiopure chiral ligands. X-ray diffraction and magnetic measurements confirmed the 2D-layered structure of the material, its absolute configuration, and its ferrimagnetic ordered state below a critical temperature of 38 K.
View Article and Find Full Text PDFWe report a ^{51}V nuclear magnetic resonance investigation of the frustrated spin-1/2 chain compound LiCuVO_{4}, performed in pulsed magnetic fields and focused on high-field phases up to 56 T. For the crystal orientations H∥c and H∥b, we find a narrow field region just below the magnetic saturation where the local magnetization remains uniform and homogeneous, while its value is field dependent. This behavior is the first microscopic signature of the spin-nematic state, breaking spin-rotation symmetry without generating any transverse dipolar order, and is consistent with theoretical predictions for the LiCuVO_{4} compound.
View Article and Find Full Text PDFPulsed magnets can produce magnetic fields largely exceeding those achieved with resistive or even hybrid magnets. This kind of magnet is indispensable in studies of field-induced phenomena which occur only in high magnetic field. A new high homogeneous pulsed magnet capable of producing field up to 55T and specially designed for NMR experiments was built and tested.
View Article and Find Full Text PDFA computational protocol for magneto-chiral dichroism and magneto-chiral birefringence dispersion is presented within the framework of damped response theory, also known as complex polarization propagator theory, at the level of time-dependent Hartree-Fock and time-dependent density functional theory. Magneto-chiral dichroism and magneto-chiral birefringence spectra in the (resonant) frequency region below the first ionization threshold of R-methyloxirane and l-alanine are presented and compared with the corresponding results obtained for both the electronic circular dichroism and the magnetic circular dichroism. The additional information content yielded by the magneto-chiral phenomena, as well as their potential experimental detectability for the selected species, is discussed.
View Article and Find Full Text PDFWe present a systematic ab initio study of enantio-selective magnetic-field-induced second harmonic generation (MFISHG) on a set of chiral systems ((l)-alanine, (l)-arginine and (l)-cysteine; 3,4-dehydro-(l)-proline; (S)-α-phellandrene; (R,S)- and (S,S)-cystine disulphide; N-(4-nitrophenyl)-(S)-prolinol, N-(4-(2-nitrovinyl)-phenyl)-(S)-prolinol, N-(4-tricyanovinyl-phenyl)-(S)-prolinol, (R)-BINOL, (S)-BINAM and 6-(M)-helicene). The needed electronic frequency dependent cubic response calculations are performed within a density functional theory (DFT) approach. A study of the dependence of the property on the choice of electron correlation, on one-electron basis set extension and on the choice of magnetic gauge origin is carried out on a prototype system (twisted oxygen peroxide).
View Article and Find Full Text PDFJ Phys Condens Matter
June 2015
In a recent publication we have shown using a QED approach that, in the presence of a magnetic field, the quantum vacuum coupled to a chiral molecule provides a kinetic momentum directed along the magnetic field. Here we explain the physical mechanisms which operate in the transfer of momentum from the vacuum to the molecule. We show that the variation of the molecular kinetic energy originates from the magnetic energy associated with the vacuum correction to the magnetization of the molecule.
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