The experimental results of the formation of polymer masks for the creation of planar microparticles of a given shape by scanning probe lithography are presented. The problems associated with the nonlinearity of the probe movement during the mask formation are considered. The possibility of increasing the lifetime of the probe by changing the mask formation procedure and (or) changing the sample temperature has been demonstrated. Improving the quality of the resulting mask is achieved through the use of chemical etching.

There is presented results studying of changes of the domain structure of a planar square microparticle with dimensions 7.5 × 7.5 × 0.04 μm under uniaxial mechanical stress. Microparticles were made from following materials: permalloy (18% Fe, 82% Ni), permendur (50% Co, 50% Fe), halfenol (16% Ga, 84% Fe), Ni, terfenol (Tb0.3Dy0.7Fe1.92). It was concluded about promising of using these materials for creating microsensors of mechanical stress and for creating straintronic devices for processing and storing information.

Co/Cu and Ni/Cu nanowires with metal layers of different thicknesses are obtained by matrix synthesis (the galvanic filling of pores in an ion-track membrane). The electrolytes are selected and the modes of electrodeposition are determined. For cobalt nanowires, the layer thicknesses vary in the range from 25 to 400 nm; for nickel nanowires, samples with thin layers from 7 to 15 nm are obtained. Electron-microscopy studies are carried out, which reveal the strict periodicity of the layers. Magnetic-force microscopy performed on a cleaved membrane with nanowires shows their division into domains and the weak interaction of neighboring nanowires. According to the results of magnetometry, the direction of the easy magnetization axis in Co/Cu nanowires depends on the geometry of the magnetic layer. At layer thicknesses greater than the nanowire diameter, the easy magnetization axis is directed along the nanowire axis; as the layer thickness decreases, it becomes perpendicular to the axis. In Ni/Cu samples (7-nm layers), the easy magnetization axis is also located perpendicular to the nanowire axis. An increase in the copper impurity content in these samples leads to a noticeable increase in the coercive force. The giant magnetoresistance effect is found in these samples with a value of about 1%; it is shown to weakly depend on the number of layers and on the copper impurity in the magnetic layer (within the studied limits).

Results of studying the domain structure of planar Ni microparticles formed on single-crystal substrates from the lithium niobate and from the potassium titanyl phosphate at different temperatures are presented. The dependence of domain sizes on the sample temperature was studied. It is shown the observed change of the domain structure is caused by the magnetoelastic effect, which arises due to the difference in the thermal expansion coefficients of the substrate and microparticles as the sample temperature changes. It is shown, the sizes of magnetic domains, up to the creation of a state with a quasi-homogeneous magnetization may be set by the substrate temperature during the microparticles formation.

Методами магнитно-силовой микроскопии были исследованы магнитные свойства (поле переключения) и переходы из многодоменного в однодоменное состояние планарных микрочастиц Co18Ni82 размером 7.5x7.5x0.03 μm3 при различных температурах. Использование в качестве подложки гексагонального монокристалла ниобата лития, обладающего отличающимися температурными коэффициентами линейного расширения вдоль разных кристаллографических осей, позволило индуцировать одноосные механические напряжения в микрочастицах путем относительно небольшого нагрева или охлаждения образца по сравнению с его температурой напыления. Показано, что за счет термоиндуцированного магнитоупругого эффекта увеличение температуры всего на 50 K может привести к семикратному уменьшению величины поля переключения. Ключевые слова: магнитоупругий эффект, магнитная силовая микроскопия, перемагничивание, ниобат лития, температура.

In work, the change of domain structure of CoNi microparticles caused by mechanical stress was studied. For this purpose, an array of identical square-shaped planar CoNi particles was formed on the surface of a polished glass substrate. Elastic bending of the substrate was used for creating of mechanical stress in the particles. It was shown by magnetic force microscopy, the magnetic structure of particles is possible to change from multidomain to quasi-homogeneous state by mechanical stress.

This article discusses the use of scanning microscopy in the study of one-dimensional nanostructures – nanowires. The nanowires were produced by matrix synthesis. Atomic force microscopy (AFM) of conical nanowires was carried out, and layered nanowires were investigated by AFM and magnetic force microscopy (MFM) methods.

AbstractNanowires (NWs) consisting of Ni/Cu and Co/Cu alternating layers with a diameter of 100 nm and layer thicknesses varying between 10 and 500 nm are prepared by template synthesis in pores of polymer track-etched membranes. Bath compositions and different regimes for pulsed electrodeposition of NWs are explored. A procedure for electrodeposition of NWs using pulses of equal charge is developed. By diminishing the amount of charge per pulse, initially we manage to lower the layer thickness to 10–15 nm, but further diminishing of charge in pulses leads to the blending of elemental composition of adjacent layers and/or formation of rod–shell nanostructures within the NWs. The coercive force (15–30 mT) and residual magnetization of our layered NWs are determined from magnetization measurements. For NWs with a layer thickness of 50–100 nm, the magnetization curves recorded in the out-of-plane and in-plane geometries are similar in shape and have similar parameters. For NWs with thicker layers (250 and 500 nm), magnetization curves are markedly different due to magnetic anisotropy (an easy magnetization axis emerges longitudinally to NWs) and interference between neighboring NWs. Magnetic force microscopy of isolated NWs identifies that the NWs comprise magnetic regions extending over ~100–150 nm. The NW can be partially remagnetized by applying an external magnetic field (+16 mT) longitudinally.

AbstractNanowires (NWs) consisting of Ni/Cu and Co/Cu alternating layers with a diameter of 100 nm and layer thicknesses varying between 10 and 500 nm are prepared by template synthesis in pores of polymer track-etched membranes. Bath compositions and different regimes for pulsed electrodeposition of NWs are explored. A procedure for electrodeposition of NWs using pulses of equal charge is developed. By diminishing the amount of charge per pulse, initially we manage to lower the layer thickness to 10–15 nm, but further diminishing of charge in pulses leads to the blending of elemental composition of adjacent layers and/or formation of rod–shell nanostructures within the NWs. The coercive force (15–30 mT) and residual magnetization of our layered NWs are determined from magnetization measurements. For NWs with a layer thickness of 50–100 nm, the magnetization curves recorded in the out-of-plane and in-plane geometries are similar in shape and have similar parameters. For NWs with thicker layers (250 and 500 nm), magnetization curves are markedly different due to magnetic anisotropy (an easy magnetization axis emerges longitudinally to NWs) and interference between neighboring NWs. Magnetic force microscopy of isolated NWs identifies that the NWs comprise magnetic regions extending over ~100–150 nm. The NW can be partially remagnetized by applying an external magnetic field (+16 mT) longitudinally.

The arrays of permalloy micron-sized particles with configurational anisotropy of shape was made by microsphere lithography technique. The properties of the particles were studied by atomic-force microscopy and magnetic-force microscopy. The magnetization distribution in particles was studied depending on the size of microspheres used in lithography process. The computer simulation of magnetic-force images of the particles was carried out. The quantitative and qualitative comparisons of shapes, sizes and reproducibility of particles fabricated by microsphere lithography and scanning probe lithography was performed.

The results of the study of changes in the magnetic structure of planar permalloy microparticles under a mechanical stress are presented. The particles were formed on glass substrates and had the square shape in the sample plane. It was shown that uniaxial mechanical stresses can be detected from the images of such particles obtained by magnetic force microscope. The ranges of effectively using of the particles for a detection of the stresses were determined depending on the geometrical sizes of the particle.

Abstract —Magnetic force microscopy has been used to study the distribution of the magnetization in permalloy microparticles with a configurational anisotropy. The triangular particles with different degrees of concavity of the lateral sides have been studied. An analysis of the results enables us to state that the particles can be in several quasi-homogeneous stable states. It is shown that the particle magnetization reversal can occur both stepwise and also via an intermediate state in the dependence on the particle orientation. It is demonstrated that the quasi-homogeneous magnetization orientation in a particle can be changed by a magnetic-force microscope probe.

Воздействие импульсного лазерного излучения на слои Si с высокой дозой имплантированных ионов Ag +