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The results of theoretical calculations and experimental data for the effective magnetic anisotropy Keff (obtained from ferromagnetic resonance measurements) of [Co(8A)∕Cu(dCu)]20 (dCu=7–22A) superlattices with a coherent interaction of the Co and Cu layers prepared by magnetron sputtering are presented. The experimental values of Keff are an oscillatory function of the thickness dCu interlayers. The computed and experimentally measured dependences Keff(dCu) are qualitatively similar; stable growth of the parameter Keff with increasing thickness of the nonmagnetic layers is observed (against the background of oscillations of the experimental curve), which is a direct consequence of the growth of axial distortions of the initial cubic structure of cobalt under the conditions of pseudomorphism. The reasons for the appearance of oscillations of Keff are discussed; the main one is the oscillatory behavior of the roughness of the interfaces of the layers with increasing dCu, resulting in synchronous oscillatio...

The energy spectrum and resonance transitions in the EPR spectrum for a four-site cluster with an exchange interaction between nearest neighbors and diagonal coupling are calculated. The cases of isotropic and anisotropic exchange couplings are analyzed. The Dzyaloshinskii–Moriya interaction is taken into account in the second case. Using the computational results, it is possible to describe the shape of the EPR absorption band of a powdered sample of the metal organic compound CENI, which undergoes appreciable changes with a change in temperature. It is shown that these changes occur because of the appearance of additional interlevel resonance transitions, whose intensity increases as temperature decreases.

Magnetic resonance was studied in magnetic fields parallel or perpendicular to the film plane in magnetron-sputtered [Co(8 A)/Cu(dCu)(111)]20 multilayers. Oscillations of the magnetic anisotropy KA and the width ΔHres of the resonance line as a function of the thickness of the copper interlayers were found in the interval dCu=7–19 A. Extrema of KA and ΔHres were observed at dCu=nd(111), where n is an integer or half-integer, and d(111)=2.087 A—the distance between the (111) planes in Cu. In addition, the distances between the neighboring maxima or minima were 1, 1.5, and 2d(111). The KA and ΔHres oscillations occurred synchronously with oscillations of the resistivity at saturation (in the field H=15 kOe) and oscillations of the magnetoresistance. An interlayer antiferromagnetic exhange interaction was found in the ranges dCu=8–11 A and dCu⩾18 A. The effects observed were due to nonmonotonic variation of the interlayer interface roughness with increasing dCu.

The EPR spectra of powder samples of a number of metalorganic compounds containing Cu2+ ions are investigated. These compounds are characterized by the presence of identical chains of octahedra forming the local environment of Cu2+, but they differ strongly in their interchain ligand structure. The resonance absorption bands permit determination of the components of the effective g factor and linewidth of individual powder particles and also their temperature dependence. It is found that the orbital singlet |x2−y2〉 is the ground state of the copper ion in all the compounds, and the exchange interaction parameters in them are estimated. The maximum exchange is observed in the system with the simplest geometry of the interchain structure in the series of compounds studied.

The temperature dependence of the resonance spectrum of [Cu(en)2H2O]SO4 single crystals is investigated in the temperature range 2.3–60 K at a frequency of ∼73 GHz. At a temperature T>15 K the angular dependence of the spectrum is described by a spin Hamiltonian of axial symmetry. At T

The ESR spectrum of a powder sample of the metal-organic complex Cu(C10H8N2)(H2O)2SO4 is investigated in the temperature interval 2–30 K. It is found that the orbital ground level of the Cu2+ ion in this compound is the Kramers doublet |x2−y2〉. The temperature dependences of the effective g-factor components and of the resonance linewidth ΔH of individual powder particles are obtained. Low-temperature broadening of the resonance line connected with short-range magnetic order in the system is observed. An estimate of the value of the exchange coupling in the magnetic system is made.