A.M. Kharlamova

The Influence of Si on Magnetic and Magneto-Optical Properties of Co/Si/Co Thin-Film Systems

The magnetic and magneto-optical properties of the Co/Si/Co thin-film samples obtained by magnetron sputtering were investigated employing magnetooptical techniques. The thickness of the Co layers was equal to 5 nm, and Si layer thickness varied in the interval of 0.2 to 3.2 nm. The magnetic saturation field of the samples under study was found to oscillate in the magnitude with the change of the Si layer thickness. This result was explained by structural features of the Co/Si/Co multilayers and the presence of the antiferromagnetic exchange coupling between magnetic layers via the silicon interlayer. The peculiarities of the magneto-optical spectra of the Co/Si/Co samples were measured and discussed.

Influence of Bi on the magnetic and magneto-optical properties of Co/Bi/Co and Bi/Co thin-film systems

The magneto-optical and magnetic properties of Co (50 A)/Bi/Co (50 A) and Bi/Co (50 A) samples are investigated. Magneto-optical investigations indicate that the shapes of transverse Kerr effect (TKE) spectra are similar for all studied samples. TKE values decrease for the Co/Bi/Co structures at t Bi > 40 A and for the Co/Bi samples at t Bi > 5 A as compared with TKE values of the single-layer Co thin film. The decrease in the volume ratio of the magnetic to nonmagnetic phases causes the reduction in the contribution of the magnetic phase to magneto-optical signals. Magnetic investigations show that the saturation field and coercivity of the studied samples increase with increasing t Bi. The exchange oscillatory coupling between Co layers through the Bi spacer in Co/Bi/Co samples with various periods (short and long) is observed in the t Bi range from 2 to 500 A. These data are explained by the dependence of Fermi energy on Bi thickness and the changes in the Bi band structure with the decrease in t Bi.

The Features of the Structural and Magnetic Characteristics of Low-Dimensional Thin-Film Systems Based on Cobalt and Copper

The results of investigation of the structural and magnetic characteristics of Co/Cu/Co thin-film systems obtained by magnetron sputtering on glass substrates are presented. The thickness of the cobalt layer in all samples was 5 nm and the thickness of the copper layer was varied from 0.5 to 4 nm. The saturation field HS of the studied samples was found to oscillate in magnitude with changes in the copper-layer thickness with a period on the order of 1 nm. The maximum values of HS are observed for the thin-film systems with tCu = 1.4, 2.2, and 3.2 nm. The hysteresis loops measured for these systems in a magnetic field applied along the easy magnetization axis of the samples have a two-stage shape, while for the samples with other values of tCu the hysteresis loops are rectangular. These data are explained by the presence of exchange coupling between the ferromagnetic layers through a copper spacer and its oscillating behavior with changing tCu.

Structural and Magnetic Properties of Fe73,5Si13,5B9Nb3Cu1 Microwires Produced by Modernized Ulitovsky-Taylor Method

Results of the investigation of the mechanical, elastic and magnetic characteristics of the “thick” Fe73,5Si13,5B9Nb3Cu1 amorphous microwires, produced by the modernized Ulitovsky–Taylor method, are presented. The cores of the Fe73,5Si13,5B9Nb3Cu1 microwires were found to have the stable geometric parameters along their length and the smooth (almost without defects) surface. The microwires are characterized by the high plasticity and the high strength. The stable geometric parameters of the Fe73,5Si13,5B9Nb3Cu1 microwires along their lengths cause the slight dispersion of magnetic anisotropy of the near-surface layers. As a result, the microwires exhibit the high homogeneity of the near-surface local magnetic properties. The strong influence of the stretching and torsion tensions on the remagnetization signal of the microwires was discovered.

Structure and properties of amorphous finemet alloy microwires produced by the Ulitovskii-Taylor method

Amorphous Fe73.5Si13.5B9Nb3Cu1 alloy microwires 19–50 μm in diameter are fabricated by the Ulitovskii-Taylor method. The mechanism of crystallization of the amorphous microwires is shown to be analogous to the mechanism of crystallization of an amorphous ribbon made of the same alloy. Microwires up to 30 μm in diameter are found to exhibit ductility upon bending. The near-surface magnetic properties of the microwires are shown to depend on the microwire diameter. The magnetic properties of the amorphous microwires are highly sensitive to elastic tensile and torsional strains in an ac magnetic field.

Structural and Magnetic Properties of Thick Fe 31 Co 34 Ni 10 (SiB) 25 Microwires Produced by the Modernized Ulitovsky–Taylor Method

Results on the study of the structural and magnetic properties of the as-cast Fe31Co34Ni10(SiB)25 thick microwires with glass shell, produced by the modernized Ulitovsky-Taylor method, are presented. The diameters of the amorphous metallic cores, d, of the microwires were equal to 55, 65, 95, 140, and 200 μm. The microwires had the stable geometric parameters along their lengths and the smooth (almost without defects) surface. The samples under study exhibited the high plasticity and high strength. The destruction of the microwires did not happen even after their full tightening into a knot. It was discovered that the glass shell of the microwires practically does not affect their magnetic characteristics. The saturation field HS and coercive force HC of the microwires raised with increasing the microwire diameter. The stable geometric parameters of the microwires along their lengths caused the slight dispersion of magnetic anisotropy in the near-surface layers. As a result, the Fe31Co34Ni10(SiB)25 microwires exhibited the high homogeneity of the near-surface local magnetic characteristics. In particular, the changes of the local magnitudes of the saturation field were revealed to be <;5%.

Features of the magnetic properties of Co/Si/Co thin-film systems

The magnetic properties of Co/Si/Co thin-film structures grown by magnetron sputtering have been studied using magnetooptical techniques. It is established that the saturation field (HS) of trilayers exhibits oscillations as a function of the thickness of the semiconductor (silicon) interlayer. This behavior is explained by structural features of the Co/Si/Co system and the presence of antiferromagnetic exchange coupling between magnetic layers via the silicon interlayer.