Interpretation of the Nature of the Mixed Form of Resonance Lines of the Electron Paramagnetic Resonance Spectrum in a New Paradigm of Spin Exchange: Abnormal "Resonance" of Non-Resonant Spins.

It is shown that the asymmetric shape of lines in the electron paramagnetic resonance spectra of paramagnetic particle solutions caused by spin exchange in bimolecular particle collisions is due to the fact that, in the experiment, under the conditions of slow spin exchange, an absorption signal of nominally resonant spins and a "resonance" dispersion signal of nominally nonresonant spins with an abnormal phase of their quantum coherence are registered simultaneously. The mixing of these two signals is different for different resonance lines in the observed spectrum. A phenomenological model is proposed that can be used to find the phase of the "resonance" signal of non-resonant spins.

Spin crossover properties of Fe(III) complexes in [Fe (bzacen)(tvp)]BPh ·nSolv chain structures: EPR study.

Two types of Fe(III) polynuclear iron(III) 1D-chain coordination compounds of the general formula [Fe (L)(tvp)]BPh nSolv, where L = dianion of N,N'-ethylenebis (benzoylacetylacetone)2,2'-imine (bzacen), tvp = 1,2-di(4-pyridyl)ethylene were synthesized and studied by the electron paramagnetic resonance (EPR) and magnetic susceptibility methods in the temperature range (100-300) К. Two types of spin-variable complexes are formed depending on the time of precipitation of the complexes from the same solution leading to differently solvated species. They have different characteristics of the local ligand field and the spin transition behavior.

Epitaxial growth and superconducting properties of thin-film PdFe/VN and VN/PdFe bilayers on MgO(001) substrates.

Single-layer vanadium nitride (VN) and bilayer PdFe/VN and VN/PdFe thin-film heterostructures for possible spintronics applications were synthesized on (001)-oriented single-crystalline magnesium oxide (MgO) substrates utilizing a four-chamber ultrahigh vacuum deposition and analysis system. The VN layers were reactively magnetron sputtered from a metallic vanadium target in Ar/N plasma, while the Pd Fe layers were deposited by co-evaporation of metallic Pd and Fe pellets from calibrated effusion cells in a molecular beam epitaxy chamber. The VN stoichiometry and Pd Fe composition were controlled by X-ray photoelectron spectroscopy.

Observation of Acoustically Induced Transparency for γ-Ray Photons.

We report an observation of a 148-fold suppression of resonant absorption of 14.4 keV photons from exp(-5.2) to exp(-0.

AgS QDs/Si Heterostructure-Based Ultrasensitive SWIR Range Detector.

In the 20 century, microelectronics was revolutionized by silicon-its semiconducting properties finally made it possible to reduce the size of electronic components to a few nanometers. The ability to control the semiconducting properties of Si on the nanometer scale promises a breakthrough in the development of Si-based technologies. In this paper, we present the results of our experimental studies of the photovoltaic effect in AgS QD/Si heterostructures in the short-wave infrared range.

Effects of Thryptophan Hydroxylase Blockade by P-Chlorophenylalanine on Contextual Memory Reconsolidation after Training of Different Intensity.

The processes of memory formation and its storage are extremely dynamic. Therefore, the determination of the nature and temporal evolution of the changes that underlie the molecular mechanisms of retrieval and cause reconsolidation of memory is the key to understanding memory formation. Retrieval induces the plasticity, which may result in reconsolidation of the original memory and needs critical molecular events to stabilize the memory or its extinction.

Nuclear Quantum Memory and Time Sequencing of a Single γ Photon.

We propose a technique for γ photon quantum memory through a Doppler frequency comb, produced by a set of resonantly absorbing nuclear targets that move with different velocities. It provides a reliable storage, an on-demand generation, and a time sequencing of a single γ photon. This scheme presents the first γ-photon-nuclear-ensemble interface opening a new direction of research in quantum information science.

Effect of the chemical structure of an equatorial ligand on the spin crossover properties of the Fe(III) complex with 4-styrylpyridine axial ligands.

In order to study the effect of the chemical structure of the equatorial ligand on the spin state of the Fe(iii) ion in complexes with invariable photoisomerizable 4-styrylpyridine axial ligands and different tetradentate Schiff bases, several new Fe(iii) complexes have been first synthesized, characterized, and studied by UV-vis, NMR, and EPR spectroscopies. The general chemical formula of the complexes is [Fe(SB)Sp]BPh·MeOH, where Sp is trans-4-styrylpyridine and SB are dianions of Schiff bases: salen, bzacen, and acen [salen = N,N'-ethylenebis(salicylaldimine) 1, acen = N,N'-ethylenebis(acetylacetonylideneimine) 2, and Hbzacen = N,N'-ethylenebis(benzoylacetonylideneimine) 3]. The results of the EPR and NMR measurements of the complexes both in the solid state and in solutions showed that the more methyl groups and less aromatic rings in the equatorial ligand, the more abrupt spin-crossover was observed in the complex.

Electron spin polarization in an Al(III) porphyrin complex with an axially bound nitroxide radical.

The generation and transfer of electron spin polarization and coherence plays an important role in quantum information technologies and spintronics. In this context, the excited state spin dynamics of molecular systems in which a stable free radical is attached to a chromophore are of particular interest. In such complexes, the coupling between the electron spin on the free radical with those on the chromophore generates excited states referred to as sing-doublet, trip-doublet, and trip-quartet.

The triplet mechanism of electron spin polarization in moderately coupled triplet-doublet rigid complexes as a source of the enhanced +1/2 ↔ -1/2 transitions.

The light-induced electron spin polarization generated in the excited quartet and doublet states of a system consisting of a chromophore with an attached radical is investigated theoretically. Excitation of the chromophore and subsequent relaxation leads to a coupled triplet-doublet spin system. In many such systems, the electronic coupling between the triplet and doublet spins is expected to be strong enough to split the spin system into so-called trip-doublet and trip-quartet states but sufficiently weak that it does not promote significant mixing between the sing-doublet and trip-doublet states.

Effect of the Diamagnetic Single-Crystalline Host on the Angular-Resolved Electron Nuclear Double Resonance Experiments: Case of Paramagnetic [BuN][Cu(opba)] Embedded in Diamagnetic [BuN][Ni(opba)].

The electron spin resonance (ESR) and electron nuclear double resonance (ENDOR) spectroscopies are frequently used to determine hyperfine () and quadrupole () tensors for the paramagnetic transition-metal complexes, which knowledge enables estimation of the spin density distribution in the complex and the assessment of magnetic exchange pathways in polynuclear molecular networks. The most accurate results can be obtained if paramagnetic complexes are isolated in a single-crystalline diamagnetic host. In this work we were able to detect angle-resolved ESR/ENDOR spectra of the paramagnetic [BuN][Cu(opba)] (opba = -phenylenebis(oxamato) complex hosted by the single crystal of diamagnetic [BuN][Ni(opba)], which allow recovery of , , and -tensors, all at once.

Superconducting switching due to a triplet component in the Pb/Cu/Ni/Cu/CoCr Fe Al spin-valve structure.

We report the superconducting properties of the CoCr Fe Al /Cu/Ni/Cu/Pb spin-valve structure the magnetic part of which comprises the Heusler alloy layer HA = CoCr Fe Al with a high degree of spin polarization (DSP) of the conduction band and a Ni layer of variable thickness. The separation between the superconducting transition curves measured for the parallel (α = 0°) and perpendicular (α = 90°) orientation of the magnetization of the HA and the Ni layers reaches up to 0.5 K (α is the angle between the magnetization of two ferromagnetic layers).

Liquid crystalline poly(propylene imine) dendrimer-based iron oxide nanoparticles.

Poly(propylene imine) dendromesogens (generations from 1 to 4) have been utilized for the synthesis and stabilization of ferrimagnetic FeO nanoparticles. Reduction of Fe(iii) with further oxidation of Fe(ii) results in the formation of highly soluble nanocomposites of iron oxides in a dendrimer, which are stable under a wide range of temperatures. The magnetic iron oxide nanoparticles were investigated by MALDI-ToF MS spectrometry and elemental analysis.

Thermally induced cyclization of -isoleucyl- -alanine in solid state: Effect of dipeptide structure on reaction temperature and self-assembly.

Thermal treatment of short-chain oligopeptides is able to initiate the process of their self-assembly with the formation of organic nanostructures with unique properties. On the other hand, heating can lead to a chemical reaction with the formation of new substances with specific properties and ability to form structures with different morphology. Therefore, in order to have a desired process, researcher needs to find its temperature range.

Fabrication of High-Temperature Quasi-Two-Dimensional Superconductors at the Interface of a Ferroelectric Ba_{0.8}Sr_{0.2}TiO_{3} Film and an Insulating Parent Compound of La_{2}CuO_{4}.

We report the first observation of superconductivity in a heterostructure consisting of an insulating ferroelectric film (Ba_{0.8}Sr_{0.2}TiO_{3}) grown on an insulating parent compound of La_{2}CuO_{4} with [001] orientation.

Balance between Triplet States in Photoexcited Orthogonal BODIPY Dimers.

The intersystem crossing (ISC) and the triplet states in two representative BODIPY orthogonal dimers were studied with time-resolved electron paramagnetic resonance (TREPR) spectroscopy. The electron spin polarization (ESP) of the triplet state of the dimers, accessed with spin-orbit charge-transfer ISC, is different from that of the monomer (spin-orbit coupling-induced ISC). The TREPR spectra show that the triplet state initially formed by charge recombination is localized on either of two subunits, with different preference and ESP patterns.

Engineering of Shallow Layers of Nitrogen Vacancy Colour Centres in Diamond Using Plasma Immersion Ion Implantation.

Sensing nano-scale magnetic field sources is at the heart of many applications in nano-science and biology. Given its very small size and high magnetic sensitivity, the nitrogen vacancy (NV) colour centre in diamond is one of the leading candidates for such applications. However, issues regarding the stability and performance of the NV centre near the diamond's surface are the major obstacle in the practical realization of theses sensors.

L1-FeNi films on Au-Cu-Ni buffer-layer: a high-throughput combinatorial study.

The fct L1-FeNi alloy is a promising candidate for the development of high performance critical-elements-free magnetic materials. Among the different materials, the Au-Cu-Ni alloy has resulted very promising; however, a detailed investigation of the effect of the buffer-layer composition on the formation of the hard FeNi phase is still missing. To accelerate the search of the best Au-Cu-Ni composition, a combinatorial approach based on High-Throughput (HT) experimental methods has been exploited in this paper.

Magnetization Blocking in Fe Dy Molecular Magnets: Ab Initio Calculations and EPR Spectroscopy.

The magnetism and magnetization blocking of a series of [Fe Dy (OH) (teaH) (RC H COO) ] complexes was investigated, in which teaH =triethanolamine and R=meta-CN (1), para-CN (2), meta-CH  (3), para-NO  (4) and para-CH  (5), by combining ab initio calculations and EPR measurements. The results of broken-symmetry DFT calculations show that in all compounds the Fe-Fe exchange interaction is antiferromagnetic and stronger by far than the Fe-Dy and Dy-Dy interactions. As a result, the lowest two exchange doublets probed by EPR spectroscopy mostly originate from the Ising interaction of the dysprosium ions in all compounds.

Crystal environment of impurity Nd ion in yttrium and scandium orthosilicate crystals.

The ESEEM spectroscopy was used to determine positions of the Nd impurity ions in YSiO single crystal. It is established that neodymium ions substitute yttrium ions in the Y2 positions with seven nearest oxygen ions. Crystal field parameters of Nd impurity centers in isotopically pure YSiO and ScSiO single crystals were determined using data of CW EPR spectroscopy and the known energy level schemes.

Polystyrenesulfonate-coated nanoparticles with low cytotoxicity for determination of copper(II) via the luminescence of Tb(III) complexes with new calix[4]arene derivatives.

The authors describe new ligands with two 1,3-diketone groups and two heteroaromatic (pyridyl or quinolyl) moieties embedded to the upper and lower rims of dibromo-substituted calix[4]arene scaffold. The ligands bind Tb(III) ions in alkaline DMF solutions to form 1:1 complexes. The strong Tb(III)-centered luminescence (with excitation/emission peaks at 330/545 nm) of the complexes results from efficient ligand-to-metal energy transfer.

Increasing the performance of a superconducting spin valve using a Heusler alloy.

We have studied superconducting properties of spin-valve thin-layer heterostructures CoO /F1/Cu/F2/Cu/Pb in which the ferromagnetic F1 layer was made of Permalloy while for the F2 layer we have taken a specially prepared film of the Heusler alloy CoCr Fe Al with a small degree of spin polarization of the conduction band. The heterostructures demonstrate a significant superconducting spin-valve effect, i.e.

Large uniaxial magnetostriction with sign inversion at the first order phase transition in the nanolaminated MnGaC MAX phase.

In 2013, a new class of inherently nanolaminated magnetic materials, the so called magnetic MAX phases, was discovered. Following predictive material stability calculations, the hexagonal MnGaC compound was synthesized as hetero-epitaxial films containing Mn as the exclusive M-element. Recent theoretical and experimental studies suggested a high magnetic ordering temperature and non-collinear antiferromagnetic (AFM) spin states as a result of competitive ferromagnetic and antiferromagnetic exchange interactions.

Hydration number: crucial role in nuclear magnetic relaxivity of Gd(III) chelate-based nanoparticles.

Today, nanostructure-based contrast agents (CA) are emerging in the field of magnetic resonance imaging (MRI). Their sensitivity is reported as greatly improved in comparison to commercially used chelate-based ones. The present work is aimed at revealing the factors governing the efficiency of longitudinal magnetic relaxivity (r) in aqueous colloids of core-shell Gd(III)-based nanoparticles.