[en] The garnet YIG:Co films have been investigated within the temperature range 10-300 K. Torque magnetometry study showed the temperature-induced spin-reorientation phase transitions. Using the Faraday effect, magnetic domain structures were visualized by optical microscope and analyzed by digital image processing technique. Temperature- and magnetic-field-induced transitions between phases with in-plane and out-of-plane magnetization were studied by the magneto-optical technique

[en] Metallic ultrathin magnetic layers can exhibit either the thickness or field-induced reorientation phase transitions (RPT - the transition from the easy magnetization axis to the easy plane). Results of both analytical analysis and simulation studies of magnetization distribution evolution approaching the RPT are presented. The transition from Kittel-like domain structure state into in-plane magnetization monodomain state undergoes through the sinusoidal domain structure. Few orders of magnitude decrease of domain size (down to nanometer scaled domains) is obtained approaching the RPT

No abstract available

[en] Photomagnetic effect have been studied in (YCa)₃(FeCoGe)₅O₁₂ epitaxial layer on gadolinium-gallium garnet. Laser radiation induced domain structure changes of investigation layer have been measured by means of Faraday effect based technique. 6 refs, 3 figs

[en] Full text: Magnetic domain structures (DS) of ultrathin films of thickness, d< lex (the exchange length) exhibit novel features: a sharp thickness dependence of domain sizes and strong reconstruction of magnetization distributions in domains related to anisotropy changes which are essential for an understanding of magnetism on the nanoscale length. The evolution of magnetic DSs and the properties of nanoscaled domains in ultrathin films and wedges with thickness dependent anisotropy are still an open problem. In such samples the reorientation phase transition from the perpendicular to in-plane magnetization state takes place with the increasing film thickness above the critical one. During the transition the DS period decreases in several orders of magnitude in a very narrow film thickness range, e.g., as the Co-film thickness increases from d=1 nm to d_l=1.79 nm the magnetization distribution transforms from large domains with sizes and geometry determined mainly by coercivity rather than magnetostatic forces into nanosized sinusoidal-like domains at d∼d_l [1]. In this work we analytically and by micromagnetic simulations describe magnetization distributions in films of different thickness and anisotropy. Applying the thermodynamic approach we show that depending on the coercivity field distribution the out-of-equilibrium domains can significantly differ in sizes from the equilibrium ones. Moreover, sizes and geometry of metastable domains depend on magnetic and thermal sample history, e.g. in experiments [2] small metastable 'frozen' by coercivity domains with the period close to the minimal one (p_min∼8πl_ex²/d, [1]) remained in the film after removal of the applied in-plane magnetic field. In the ultrathin regime (d< l_ex) the relationship between the periods of metastable (p) and equilibrium (p₀) domains is given by ln p/p₀=± πh_cp/d , where h_c=H_c/4πM_s is the normalized coercive field, M_s is the magnetization of saturation, and the sign is related with the direction of magnetization process in which the metastable domains were created. Thus, any potential barriers (related with coercivity, sample morphology, shape, and coverage) on the DS energy landscape can affect the domain sizes. The difference in the total energies of the equilibrium and metastable domains is typically less than 1%. However, even such a small energy difference leads to a significant difference in the sizes of equilibrium and out-of-equilibrium domains. Metastable magnetization states can also appear in laterally size limited ultrathin magnets. New types of equilibrium and metastable domain-like magnetization distributions in nanodisks and nanowires we found by micromagnetic simulations. The metastable states could easily be switched by a small external field and therefore used as medium for high density perpendicular recording with highest frequencies. The critical disk radius and wire width under which the magnetization distributions become out-of-plane ones were found by simulations and analytically. The work was supported by Marie Curie Fellowships for 'Transfer of Knowledge' ('NANOMAG-LAB', N 2004-003177) and the Polish State Committee for Scientific Research (Grant No. 4 T11B 006 24). [1] M. Kisielewski et. al., Phys. Rev. B (2004) 69, 184419. [2] M. Kisielewski et. al., J. Appl. Phys. (2003) 93, 6966

[en] Microscopic model was proposed for the description of cubic and uniaxial magnetic anisotropy changes under the influence of non-polarized or linearly polarized light. The model was developed for either semiconductor or isolator with ions giving different contribution to magnetic anisotropy after light excitation. Linearly polarized light-induced magnetic anisotropy changes are much more stable than the ones induced by non-polarized light

[en] By micromagnetic simulations and analysis we study domain size and magnetization distribution evolution under changes of magnetic fields applied parallel to ultrathin film, H_||. Domain wall energies and domain periods were calculated for H_||=0 and H_|| close to the effective anisotropy field. The huge influence of the demagnetizing effect on the equilibrium domain period has been found. Simulated domain periods are in good agreement with those obtained analytically

[en] The magnetic anisotropy of ultrathin Co magnetic films epitaxially deposited on vicinal Si(1 1 1) are investigated using ferromagnetic resonance techniques. The experimental data were discussed, taking into account the following contributions to the total magnetic anisotropy energy: magnetocrystalline anisotropy, step-induced uniaxial in-plane anisotropy and perpendicular uniaxial anisotropy. Magnetic anisotropy constants were fitted from experimental results

[en] Based on commercial Burleigh METRIS^TM-2000 Atomic Force Microscope two methods of magnetic force measurements were realised. The developed system was successfully applied for study of magnetic structure of both YIG-garnet and CoNi/Pt magneto-optic layers. (author)

[en] Thickness-dependent changes of the domain period, initial susceptibility and saturation field in ultrathin films was theoretically analyzed considering the equilibrium state of the domain. The experiment was performed on artificially stabilized tetragonal-ordered gold-iron films with thickness varying from 3 up to 50 monolayers. Domain structure and magnetization processes were studied using magneto-optical techniques. Square hysteresis loops were registered for intermediate film thickness