The distribution of Co2+ ions over sublattices and structurally nonequivalent positions in the unit cell of the crystal lattice of a single crystal of lithium gallium spinel Li0.5Ga2.5O4 is shown. This distribution determines the properties of both mono- and nanocrystalline substances. The distribution is obtained by a special technology and is manifested in the electron paramagnetic resonance (EPR) spectra. The distribution of Co2+ ions depends on the structural and magnetic nonequivalence. The structural and magnetic nonequivalence causes a multiminimum behavior of the crystal field potential in the unit cells of single crystals at the locations of Co2+ ions. The Co2+ ions are found in complexes with tetrahedral and octahedral oxygen ions. Three types of EPR spectra of Co2+ ions have been found and investigated. The Co_tetr^2 + spectrum is attributed to the Co2+ ion, which replaces the Ga3+ ion located in a tetrahedral oxygen environment. The spectrum of the Co_oct^2 + ion located in the crystal field with axial symmetry belongs to the Co2+ ion replacing the Li+ ion located in an octahedral oxygen environment. The spectrum of the Co_oct^2 + ion located in a low symmetry crystal field belongs to the Co2+ ion replacing the Ga3+ ion located in an octahedral oxygen environment. The nearest cationic environment of the ion creates rhombic distortions due to the different valence numbers of Li+ and Ga3+. The results of studying the angular dependences of the spectra show the presence of four and twelve magnetically nonequivalent positions in the unit cells.

The study is part of biomedical nanotechnology and is carried out by probing these systems using the Electronic Spin Resonance (ESR) method. The paper investigates glass ionomer cement powder widely used in dental practice Glass ionomer cement CX - Plus Triplekit - TM. For analysis of properties of glass-ionomer cement ESR radiospectroscopy is used in the range from low (T=4.2K) to room (T=300K) temperatures. A new characteristic of compounds with nanocomplexes of magnetic iron ions Fe3+ is applied.

The study is part of nanomedical biotechnology and is carried out by probing these systems using the Electronic Spin Resonance (ESR) method. The paper investigates Glass Ionomer Cement powder widely used in dental practice Glass Ionomer Cement C-Plus Triplekit-TM. To assess the quality of Glass Ionomer Cement and use ESR radiospectroscopy in the range from low (T=4.2 K) to room (T=300 K) temperatures. A new characteristic of compounds with nanocomplexes of magnetic iron ions Fe 3+ is applied. Key words: Electronic Spin Resonance (ESR), nanocrystals, crystal field potential, intensity of ESR lines.

Coordination compounds containing the Fe3+ ions like sodium salt Na[FeO6(C10H8N)(3)], kaolinite Al-2[Si2O5].(OH)(4), metalloproteins (Ferritin, Maltofer, and Ferrum Lek) find a wide application. The analysis of the properties of these compounds has demonstrated a developed crystal structure. The diffractogram of Ferritin included an amorphous component. Within the temperature range of 4.2-300 K, all the compounds are characterized by transformation and mutual transfer of the lines of electron paramagnetic resonance spectrum of the Fe3+ ions (EPR). This fact allows estimation of a dynamical characteristic of the nearest neighbor environment of Fe3+.

A self-organization of eight structurally and magnetically nonequivalent positions of manganese Mn2+ ions in the unit cell of a single crystal of the lithium–gallium Li0.5Ga2.5O4 spinel is demonstrated. These ions are self-distributed over such positions and minima of the crystal field potential. The self-organized structures form during the crystal growth. Such a self-distribution of manganese ions is observed and studied in the electron paramagnetic resonance (EPR) spectra.

Self-organization of eight structurally and magnetically non-equivalent positions of manganese ions Mn2+ in a unit cell of single-crystal lithium-gallium spinel Li0,5Ga2,5O4 is demonstrated. The ions are self-distributed over these positions and the minima of the crystal field potential. Self-distribution of manganese ions becomes apparent in the spectra of Electron Paramagnetic Resonance (EPR).

Self-organization of twelve structurally and magnetically non-equivalent sites and self-distribution of magnetic ions of chromium over these sites at the minima of the crystal field potential in a unit cell of single crystal lithium-gallium spinel Li0.5Ga2.5O4 is considered. The form of the crystal field potential at the location of a magnetic ion is determined by the nearest neighbours. If the crystal symmetry is similar to the cubic one, structurally non-equivalent ion positions are formed. In this case, the compound contains the related number of magnetically non-equivalent positions of the magnetic ion that are found in the electron paramagnetic resonance spectra.

The spin-wave resonance spectrum is a characteristic of a magnetic film. The surface mode of this spectrum depends on the magnitude and nature of the stress state of the surface layer of the film. Parameters of this mode are independent on the film conductivity.

A new parameter of compounds of different nature (organic, inorganic, single- and polycrystal ones) containing complexes with magnetic probes has been developed. That is the height of the potential barrier of the crystal field. The barrier height characterizes the nature of the neighbor structure of a complex with a magnetic ion that can be distorted in accordance with the nature or the growth technology of the compound. To analyze the spectra of electron spin resonance of the Fe3+ ions in organic compounds of different structure symmetry in temperature range of 4.2 K-295 K, models of the effect of multi-minimum potential of crystal field were used.

Certification of new magnetic materials requires high-precision nondestructive methods. The method of measuring the magnetostriction constant of films by studying low-frequency magnetic susceptibility at elastic deformation of the films is proposed. The method allows a tenfold improvement of the accuracy of measurements of the magnetostriction constant as compared with the methods applied earlier.

AbstractCertification of new magnetic materials requires high-precision nondestructive methods. The method of measuring the magnetostriction constant of films by studying low-frequency magnetic susceptibility at elastic deformation of the films is proposed. The method allows a tenfold improvement of the accuracy of measurements of the magnetostriction constant as compared with the methods applied earlier.

The modern progress of bionanotechnologies and molecular electronics requires development of new organic materials with specific characteristics for formation of ultrathin films with specified magnetic or conductive properties. Here we need new experimental and computing methods creation. In this work a new effect is experimentally discovered in temperature behavior of electronic properties of the complex with a magnetic probe (iron ion) in poly(ortho-methoxyaniline) (PoMA). Using quantum chemical calculation we determine the structure of the magnetic probe's immediate environment. The electron structure of the polymer specifies peculiarities of its doping and charge transport. The iron magnetic probe allows measuring of the complex's electron structure dynamic characteristics in the polymer using the method of electron spin resonance for temperature range T = 4.2-295 K. The height of the barrier between the minima of potential of the intramolecular electric field of the complex is established.

The conductivity and electron spin resonance (ESR) of polyaniline (PANI) – polymethylmethacrylate (PMMA) nanoscale blends have been studied. It has been found that the dependence of the specific volume conductivity on the PANI content in PANI-PMMA blends can be described by a percolation model with extremely low percolation “threshold” in the range 0.8–2% (vol.). The temperature dependence of ESR for the higher percolation threshold of a PANI- PMMA blend has been studied in the temperature range 4.2–300 K. It has been shown that a g-value for unblended PANI and the PANI-PMMA composites is close to the free spin value and is constant at all temperatures, while the spin population is temperature-depended. Based on the temperature dependence of ESR, the existence of two types of spins (localized and delocalized) in the polymer blend is suggested.