A change in the quasistatic magnetic susceptibility in thin plates of iron borate (FeBO3), which is a weak ferromagnet, has been revealed at adsorption of water molecules. The measurements have been performed at room temperature with the use of the magneto-optical Faraday effect. The change of the susceptibility in saturated water vapors is about 30%. The observed effect is reversible. The time of establishing the susceptibility after the introduction of water vapors is 1.5 min, which is twice as large as the time of establishing the susceptibility after the evacuation. The effect is explained by the appearance of uniaxial surface magnetic anisotropy in the basal plane because of the adsorption of water molecules.

An atomic-force microscopy study has surprisingly revealed that ultrathin copolymer films fabricated according to Langmuir technology constitute a network of tangled filaments. A long-range order is absent in the samples. The observed filaments consist of several parallel-packed copolymer chains. The shape of ferroelectric domains in a film is independent of the direction of copolymer chains. Each domain includes a large number of filaments. The nature of high-temperature (ferroelectric) and low-temperature phase transitions has been discussed in terms of structural data.

With the use of magneto-optical Faraday effect effective field of perpendicular magnetic anisotropy of iron garnet films is measured in vacuum and in the atmosphere of water vapor. It is established that a decrease of the mentioned field takes place due to adsorption of the water molecules by 20% in comparison with the value of field in vacuum. This result is in accordance with the conclusion reached on the base of investigation of influence of water molecules adsorption on domain structure of iron garnet films earlier.

Liquid-crystal-based films of different thicknesses, fabricated by the Langmuir technology, have been studied. Previously, we revealed a structural phase transition in these films at a temperature of ∼75°C. To clarify the nature of this transition, the temperature dependences of the capacitance and conductance of these films have been investigated. The results obtained indicate that the samples contain a ferroelectric phase, beginning with one monolayer. The film structure imperfection has been revealed using atomic force microscopy, which explains the size of the temperature range in which the phase transition is observed.

Liquid-crystal films prepared by different procedures and having different thicknesses were studied. A structural phase transition was found in these films at ∼75°C. The nature of this transition was examined by investigating the temperature dependences of the electric capacity and conductivity of the films; the optical absorption and reflection spectra were also studied. It was concluded that the samples contained a ferroelectric phase. The structure of the films was studied by atomic force microscopy. As a result of the structural studies, the peculiarities of the temperature dependences of conductivity and capacity, in particular, the temperature range in which the phase transition was observed were explained.

Langmuir films of various thicknesses, fabricated based on liquid crystals, have been studied. Previously, a structural phase transition at a temperature of ∼75°C was detected for these films. To determine the nature of this transition, the temperature dependences of the capacitance and conductance of the metal-Langmuir film-metal structures have been measured. The results obtained suggest that the ferroelectric phase in the studied samples exists beginning with one monolayer. The length of the temperature interval in which the phase transition is observed indicates a film structure imperfection.

The temperature dependences of diffuse reflection spectra and the polarization of light reflected from ultrathin Langmuir films based on liquid crystals are studied. The results are compared to the experimental data obtained on thicker liquid films. The dependences of the electric capacity of metal-film-metal structures on temperature are measured. The maximum for ultrathin films lies near 75°C, indicating the occurrence of a ferroelectric phase transition. Features in the intensity and polarization of the reflected light are registered at the phase transition temperature. It is concluded that the generality of the results obtained using samples of both types indicates the existence of a mesomorphic phase in Langmuir films. The observed differences could be associated with either dimensional effects or differences in the structures of the films.

The reversible change in the domain structure and the magnetic domain width in bismuth-containing iron garnet films with an easy magnetization axis oriented normal to their surface during adsorption caused by hydrogen bonds is studied by a magnetooptical method. The dependence of the domain width on the vapor pressure of methyl alcohol or water in a cell with a sample is determined, and the time dependence of the domain width induced by the adsorption-desorption processes occurring between methyl alcohol molecules or water molecules on the film surface is studied. A model is proposed to explain the detected effects.

Due to water molecules adsorption the reversible change of domains width and domain structure reconstruction in bismuth-doped ferrite-garnet thin films with perpendicular magnetic anisotropy was observed. The change of domains width was 15% in saturated water vapor at room temperature. The decrease of domains width is explained by the reduction of effective perpendicular magnetic anisotropy constant due to water molecules adsorption.

The adsorption isotherms of water molecules, absorption spectra, and spectra of diffuse scattering and polarization of reflected light are studied for ultrathin Langmuir films prepared based on liquid crystals. A structural phase transition near 70°C is detected. Some specific features of the reflection spectra at the phase transition temperature are found. Suggestions are made regarding the nature of the phase transition.

The isotherms of water molecule adsorption and the spectra of absorption, diffusion reflection, and polarization of reflected light for hyperfine Langmuir films that were fabricated based on liquid crystals are investigated. Singularities in the reflection spectra at the temperature of the structural phase transition (∼70°C) are revealed. Some reasonable assumptions on the nature of the phase transition are made.

It has been found using the Faraday-effect magneto-optic method that the width of magnetic domains of the labyrinth domain structure in bismuth-containing iron garnet films with perpendicular anisotropy changes considerably after the adsorption of methanol molecules. A maximum change in domain width of 50% has been observed in methanol saturated vapor. This effect is reversible. A decrease in domain width under adsorption has been attributed to a decrease in the effective constant of the perpendicular magnetic anisotropy of the film caused by the adsorption of methanol molecules.