Rare-earth epitaxial thin films of Tb and Gd of the thicknesses between 2 nm and 16 nm were deposited by means of molecular beam epitaxy method. The roughness of the rare-earth films measured by scanning tunneling microscopy was fonnd to be in the range of 1-4.5 nm. The influence of the roughness on the dipolar anisotropy and magnetocrystalline surface anisotropy was estimated. The magnetic measurements have shown that the Gd layers deposited on the Y buffer layers had an easy plane anisotropy. However, for 2 nm thick Gd layer deposited on W buffer layer the perpendicular anisotropy was observed. According to the roughness analysis the possible sources of the perpendicular anisotropy in this sample is mainly the magnetoelastic anisotropy, but the presence of the magnetocrystalline surface anisotropy also cannot be neglected.

The surfaces of Tb epitaxial thin films were investigated by means of scanning tunnelling microscopy (STM) on the samples deposited by molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) methods. The crystal structures of films were controlled in situ by reflection high energy electron diffraction (RHEED). Different magnetization loops were observed depending upon the film roughness. Smooth samples show magnetic anisotropy with an easy plane, which is not observed in the case of rough samples. The interpretation of the magnetic properties of Tb epitaxial films given is based on the STM and RHEED measurements.

Cr/Tb/Cr thin films have been obtained by pulsed laser deposition (PLD) on sapphire (112̅0) substrates. The crystal structure of the films was characterised in-situ by means of reflection high energy electron diffraction (RHEED) and Auger spectroscopy (AS) and ex-situ by X-ray grazing incidence diffraction (GID) and scanning tunnelling microscopy (STM). The deposition of chromium on the Tb(0001) layers at 300 °C was found to lead to the formation of three Cr(110) crystalline domains. Chromium deposited on Tb(0001) initially (first 50 Å) at room temperature and then at 300 °C grew epitaxially in the [111] direction and formed two Cr(111) crystalline domains shifted by 30°. Due to the lower density of the atoms in Cr(111) plane, compared to the Cr(110) and Cr(001) ones, this orientation is interesting for magnetic studies.

The structure and magnetic properties of CoCu multilayers, grown on a float glass, in a molecular beam epitaxy (MBE) system are discussed. Structural characterization of samples was performed in-situ by means of a reflection high-energy electron diffraction (RHEED) and Auger electron spectroscopy (AES), as well as ex-situ by X-ray reflectometry. For the first time, we show successful analysis of layered structure of metallic multilayers by scanning tunneling microscopy (STM). Magnetization and in-plane magnetoresistance were measured as functions of Co and Cu sublayer thicknesses. The evidences of oscillatory coupling of magnetic sublayers with varying thicknesses of nonmagnetic spacer are presented. CoCu multilayers also display giant magnetoresistance (GMR) effect. The influence of buffer layer roughness on GMR is clearly shown.

A novel technique for measuring differential lattice dilation by scanning tunneling microscope is proposed. The method was used to measure the metastable lattice dilation caused by a deep-shallow phototransformation of bistable In impurities in CdF2 crystals. A total linear crystal shrinkage of 1.8×10−6 results from a partial counterbalancing of the lattice contraction associated with the photoionized deep localized In state by a lattice expansion caused by weakly bound electrons at the shallower hydrogenlike state of the bistable In donors.

UHV deposited magnetic Co/Cu multilayers were investigated by means of scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Surface of the sample i.e. upper covering layer in ''plane'' configuration and individual sublayers in ''cross-section'' configuration were investigated. A possibility of structure characterization of metallic multilayers by STM and AFM in the cross-section configuration is demonstrated.

Lattice relaxation accompanying phototransformation of In bistable centers from the ground, deep state to the shallow state in CdF2 crystal has been measured with the use of scanning tunnelling microscope.It is shown that relatively small macroscopic changes of the crystal length in the order of 1.8 x 10 -6 accompany the phototransformation of In ions.Lattice expansion upon the influence of population of shallow donor levels in CdF2 explains the observed small changes of lattice constant during the process.

Scanning tunneling microscopy images and scanning tunneling spectroscopy characteristics were measured at 4.2 K in liquid helium bath on the cleaved in air a-b surface of Bi2Sr2CaCu2O8 (BSCCO-2212). Electronic densities of states and superconductivity parameters Delta and Gamma evaluated from dI/dV characteristics depend on tip-sample distance s: with shortening of the distance s superconducting gap structure becomes more distinct, i.e. Delta increases and Gamma decreases. We explain this phenomenon as a non-vacuum tunneling, where for longer s tunneling electrons reach only the surface contamination layer on non-metallic BiO top-surface layer, whereas for shorter s tunneling electrons penetrate also deeper lying CuO layers reflecting their superconducting properties. The dependence of Delta on s is evaluated. This result allows to understand better the non-vacuum scanning tunneling microscopy imaging: by adjusting properly the tip-sample distance one can select suitable local density of states contributing dominantly to the scanning tunneling microscopy images taken on BSCCO.

Contraction of CdF2 crystals during phototransformation of In bistable centres has been measured with use of scanning tunnelling microscope. The observed change of the lattice constant (-1.8x10(-6)) is metastable at liquid helium temperature. This result confirms that the large lattice relaxation is responsible for the metastability of In dopant in CdF2.

Cleaved in air a-b surface of Bi 2 Sr 2 CaCu 2 O 8 (BSCCO-2212) was measured by means of STM and STS at 4.2 K in liquid hellium bath. From fitting experimental conductivity curves by Dynes' function two superconductivity parameters Δ (gap value) and Γ (smearing parameter) were obtained. The shape of gap structure superimposed on d I /d V characteristics depends on tip-sample distance, what is expressed by the increase of Δ and decrease of Γ with shortening of s . The phenomenon of becoming gap structure more distinct when approaching the tunneling tip to the surface is explained by us as the non-vacuum tunneling, where the surface contamination layer on non-metallic BiO top-surface layer strongly influences the tunneling process. Only for s short enough tunneling electrons penetrate to deeper situated CuO layers and reflect their superconducting behaviour. Non-vacuum STM images are therefore sensitive to the tip-sample distance adjustment. The dependence of gap parameters on lateral position of the tip above the sample can also occur. In such cases STS enables to state which elements of the image belong to the topography of the surface and which to its electron density of states.

The results of the scanning tunneling microscopy and spectroscopy (STM/STS) as well as atomic force microscopy (AFM) measurements on the bismuth cuprate superconductors Bi2Sr2CaCu2O8 (BSCCO) in the a-b plane are reported in this paper.Room-temperature STM/AFM has been used to study the BSCCO single crystals. Their layered crystalline structure allows one to prepare them by cleaving the atomically flat surface. Experiments have shown quits a stability of the cleaved surface and it is possible to observe reproducible STM images of the fresh surface in the air. The micromorphology and step heights in the c direction corresponding to multiple values of the unit cell have been investigated. Initial tests in air have shown that the STM was able to etch the BSCCO surface in a layer-by-layer process of subsequent removal of non-metallic (BiO) and metallic (CuO2) planes. We have also observed large areas with very stable and reproducible tunneling spectra (I-V and dI/dV) as a function of position and tip-sample spacing.Contrary to STM, AFM imaging does not modify the examined surface and reveals the surface covered with uniformly corrugated (within 1 nm range) granules, arising due to the surface degradation of the BSCCO material.

The low temperature scanning tunneling microscope (LTSTM) is used to study the local electronic properties on different crystallographic planes of Bi2Sr2CaCu2Oy single crystals in their normal and superconducting states. In different locations selected on the topographic images the I–V characteristics are measured at 4.2 K. In particular locations various features are observed: the superconducting gap, the Coulomb blockade and resonance tunnelling. Most of the observed spectroscopic characteristics indicate the strong Coulomb blockade induced by surface or impurity states. On some a−c planes of single crystals in the superconducting state the individual Cu-O and Bi-O layers can be recognized on the STM images owing to their different contributions to superconductivity.

Surfaces of amorphous ribbon Fe70V10B20 were observed by means of the scanning tunneling microscope before and after the annealing in vacuum. The topographic images of the air-side surfaces after annealing are similar in the x-y plane and different in the z-direction. From the scanning tunnelling microscope images some information on the crystallization of amorphous ribbons can be deduced.

The hysteresis of tunneling resistance in Gd/GdOx/Fe and Fe/GdOx/Fe junctions in the external magnetic field has been observed. The relative changes of tunneling resistance were of order 2.5–7.7%. The domain structures and magnetization reversal processes in the area of tunneling junctions were investigated by defocused electron microscopy. We found that the ferromagnetic coupling between electrodes of the junction strongly modified the domain structures and magnetization reversal processes in the area of tunnel junction. The hysteresis of tunneling resistance was closely connected with magnetization processes in the junction area. We estimated the polarization of tunneling densities of states for Fe electrodes to be not lower than 17% and the change of barrier height corresponding to the barrier spin filtering effect to be of order 1 meV.

The topographic images of a Bi0.7Pb0.3SrCaCu1.8Ox single crystal were studied by means of the scanning tunneling microscope. The structure of terraces and steps seen on the surface reflects the crystallographic structure of bulk.

Surface topography of the high-T c superconductor BiSrCaCu 2 O x has been investigated by means of scanning tunnelling microscope. The measurements were performed on the natural surface of ceramics material in air at room temperature. It can be deduced from the surface images, that bulk orthorhombic crystal structure extends to the surface. The surface seems to be uniform metallic in character and not drastically contaminated. Regular steps observed on the surface correspond to the dimension of the unit cell in z direction or its multiples.