Possible magnetization states of a cubic ferromagnetic crystal having easy magnetization directions parallel to the cube axes (as in Fe + 3 mass % Si alloy) can be represented using a regular octahedron, as first shown by Néel. This model is developed to derive rules that govern shapes and relative volumes of the differently magnetized domains needed to produce mean magnetization lying in a plane of any orientation. Single-crystal plates of Fe + 3 mass % Si alloy not containing an easy-magnetization direction, such as plates parallel to (112) studied in this work, are in general subdivided into a hierarchy of domains that in spatial scale diminish from specimen interior towards specimen surfaces. X-ray topography offers a non-contacting method of mapping domain configurations. Under appropriate diffraction conditions the strains associated with 90° Bloch walls generate strong diffraction contrast. In X-ray transmission topographs the superimposition of contrast from surface closure domains upon that of inner domains generally gives rise to highly complex images from (112) plates. However, with specimen thicknesses less than 20 μm the patterns can become sufficiently simplified to make possible the identification of shapes and magnetization axes of all domains present. A pattern in this class is illustrated, and interpreted with the aid of the octahedron. Reasonable agreement is found between the observed size scale of the domains and that calculated for minimum energy in the domain structure proposed.

The magnetization reversal process in domain walls of bubble lattices in magnetic garnets is investigated visually and photoelectrically. The use of the anisotropic dark-field method allows us to explain the nature of two types of hysteresis loops, i.e. exhibiting single and double jumps. Bubble lattice consisting of χ bubbles (i.e. bubbles in the state S = 1, p = 0) exhibit double-jump hysteresis loops, connected with the transition to the 1H bubble state. Bubble lattices made up of bubbles in the state S = 0, p = 2 exhibit single-jump behaviour.

Domain structures of two low coercivity (Hc/Hk ≈ 0.02) and one medium coercivity (Hc/Hk ≈ 0.05) films were observed by the colloid-scanning electron microscopy (SEM) method in d.c. magnetic fields applied normal to the surface. The dependence of the submicron domain period on ascending and descending fields was measured. Anhysteretic curves were obtained by the superposition of a slowly decreasing a.c. field on the given d.c. field. The field dependence of the anhysteretic domain period is compared with the theory of Kooy and Enz. In addition to the visual measurement, the domain period was also determined by a two-dimensional Fourier analysis of the SEM photographs.

Using the colloid-scanning-electron-microscope (SEM) method, an investigation was conducted of the domain structure of CoCr films (400-1740 nm thick) at different points of the hysteresis loop. In some cases, an AC field exceeding the value of the coercive force was applied in addition to the DC field. For low-coercivity samples (H/sub c//H/sub k/ approximately 0.02) a bubble structure, which is e...

The domain structure of a CoCr film was studied in different magnetic fields using the method of a combination of the colloid technique and scanning electron microscopy (colloid-SEM method). The results obtained are presented and the advantages of this method are discussed.

The dependence of the submicron domain period of CoCr films in ascending and descending fields (dc: 8-320 kA/m; superposed ac: 0-55 kA/m) normal to the surface was investigated using the colloid-SEM method. Low coercivity samples (Hc/Hk ~ 0.02) were measured. Comparison with calculations furnished fair agreement in contradistinction to samples having H c/Hk ~ 0.05. The exchange constant A was deteremined from the thickness dependence of the domain period.

Differential susceptibility measurements in low in-plane fields showed up a new peak assumed to be caused by magnetization reversal inside the Bloch walls (BW). Highly sensitive measurements carried out subsequently on different domain structures yielded various new parameters such as the BW hysteresis curve, the integral saturated and remanent BW moments and the internal BW coercivity. The mechanism proposed for the observed phenomena is based on the reversible and irreversible motion of Bloch lines inside the Bloch walls.

The paper presents magnetization curves of bubble lattices in garnet samples of composition (YSmLuCa)3(FeGe)5O12, in which we observed a discontinuity in the magnetization at a certain negative value of the external magnetic field applied normal to the sample surface. This points to an anomaly in the behaviour of the existing honeycomb domain structure. The proposed theoretical interpretation of this behaviour is based on the interaction of closely spaced pairs of Bloch walls.

A theory is given of FMR of a close packed hexagonal lattice of magnetic bubbles in a thin uniaxial ferromagnetic layer as a function of the intensity of an external magnetic field applied normal to the easy axis i.e. in the plane of the layer. The solution is based on a model which permits the inclusion of the effect of inhomogeneities of the hf demagnetizing field inside the specimen. The theory yields three magnetic modes which are in very good agreement with a number of experiments carried out on magnetoplumbite platelets. The physical interpretation of the results is discussed. Es wird eine Theorie der FMR eines dichtgepackten hexagonalen Gitters von Magnetblasen in einer dünnen uniaxialen ferromagnetischen Schicht in Abhängigkeit von der Intensität eines äußeren, senkrecht zur Achse der leichten Magnetisierbarkeit, d. h. in der Ebene der Schicht, angelegten Magnetfelds angegeben. Die Lösung beruht auf einem Modell, das die Einbeziehung des Einflusses von Inhomogenitäten des demagnetisierenden HF-Feldes in der Probe erlaubt. Die Theorie liefert drei magnetische Moden, die in sehr guter Übereinstimmung mit einer Anzahl von Experimenten sind, die an Magnetoplumbitplättchen ausgeführt werden. Die physikalische Interpretation dieser Ergebnisse wird diskutiert.

The general manner of how the presence of an additional uniaxial anisotropy changes the directions and the relative “strengths” of the easy axes of magnetization in an originally cubic material is understood. Both qualitative reasoning and the exact quantitative description are given including the transformation formulas for the general geometry of the uniaxial axis with respect to the cubic system. Das allgemeine Verhalten, wie die Anwesenheit einer einachsigen Anisotropie die leichten Richtun-gen und deren relativen „Stärken”︁ in einem ursprünglich magnetisch kubischen Material beein-flußt, wird untersucht. Dabei wird diese Anordnung nicht nur qualitativ diskutiert, sondern es wird auch eine exakte quantitative Beschreibung mit Angaben der Transformationsformeln für die allgemeine Geometrie der einachsigen Anisotropie mit Bezug auf das kubische System an-gegeben.

physica status solidi (a)Volume 63, Issue 1 p. K87-K92 Short Note Bloch wall energy including cubic and uniaxial anisotropy J. Kaczér, J. Kaczér Institute of Physics, Czechoslovak Academy of Sciences, Prague Search for more papers by this author J. Kaczér, J. Kaczér Institute of Physics, Czechoslovak Academy of Sciences, Prague Search for more papers by this author First published: 16 January 1981 https://doi.org/10.1002/pssa.2210630170Citations: 5 Na Slovance 2, 18040 Praha 8, CSSR. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume63, Issue116 January 1981Pages K87-K92 RelatedInformation

The radial magnetization distribution of an easy-plane cylindrical specimen is investigated by the Euler-Lagrange variational method. The resulting non-linear differential equation shows, that the magnetization in the “core” of the cylinder points preferentially along its axis, while for larger radii it circulates near the easy-plane.

physica status solidi (a)Volume 49, Issue 1 p. K81-K83 Short Note Contribution to the technology of GdCo films J. Čermák, J. Čermák Department of Physics K 203, Czechoslovak Technical University, PragueSearch for more papers by this authorV. Tvarožek, V. Tvarožek Department of Microelectronics, Slovak Technical University, BratislavaSearch for more papers by this authorR. Harman, R. Harman Department of Microelectronics, Slovak Technical University, BratislavaSearch for more papers by this authorJ. Kaczér, J. Kaczér Institute of Physics, Czechoslovak Academy of Sciences, PragueSearch for more papers by this author J. Čermák, J. Čermák Department of Physics K 203, Czechoslovak Technical University, PragueSearch for more papers by this authorV. Tvarožek, V. Tvarožek Department of Microelectronics, Slovak Technical University, BratislavaSearch for more papers by this authorR. Harman, R. Harman Department of Microelectronics, Slovak Technical University, BratislavaSearch for more papers by this authorJ. Kaczér, J. Kaczér Institute of Physics, Czechoslovak Academy of Sciences, PragueSearch for more papers by this author First published: 16 September 1978 https://doi.org/10.1002/pssa.2210490172AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 L. J. Tao, R. J. Gambino, S. Kirkpatrick, J. J. Cuomo, and H. Lilienthal, 19th 3 M Conf., Boston, December 1973. 2 P. Chaudhari, J. J. Cuomo, R. J. Gambino, S. Kirkpatrick, and L. J. Tao, 20th 3 M Conf., San Francisco, December 1974. Volume49, Issue116 September 1978Pages K81-K83 ReferencesRelatedInformation

Measurements are made of the magnetizing curves of single crystals of U3As4 for some directions in the (110) plane. Of principal interest is the behaviour of the angular dependence of the first order field induced phase transition in the neighbourhood of the hard directions <100>. The measurements are carried out in pulsed fields up to 23 T (230 kOe) at temperatures of 77 K. The resultant experimental curves served as a basis for a theory of this first order phase transition. Es werden die Magnetisierungskurven von U3As4-Einkristallen für einige Richtungen in der (110)-Ebene mitgeteilt. Von besonderem Interesse ist das Verhalten der Winkelabhängigkeit des feldinduzierten Phasenübergangs erster Ordnung in der Nähe der harten <100>-Richtung. Die Messungen werden in Impulsfeldern bis zu 23 T (230 kOe) bei einer Temperatur von 77 K durchgeführt. Die erhaltenen Kurven dienen als Grundlage für eine Theorie dieses Phasenübergangs erster Ordnung.

The ferromagnetic resonance of two magnetostatically coupled uniformly magnetized coaxial cylinders (bubble inside circular platelet) of arbitrary geometry was investigated versus the applied field. Magnetic charges set up by the different demagnetizing factors of the inner and outer (hollow) cylinder are responsible for line splitting. Numerical results are presented graphically.

Recent experimental and theoretical work on the ferromagnetic resonance absorption in unsaturated samples of uniaxial materials containing mutually interacting bubbles is reported. The experiments were carried out on magnetoplumbite platelets 5 to 36 μm thick in the frequency range 16 to 50 GHz with fields both parallel and normal to the easy axis. The originally single absorption line for saturated samples splits into a number of lines the positions of which are practically independent of thickness dependent, however, on the magnetization suggesting magnetostatic modes. Interacting equiphase bubble sublattices precessing in different modes are proposed to explain these bubble mode resonances (BMR).

Formulas are presented for the magnetostatic energy and the demagnetizing factors of two uniformly magnetized coaxial cylinders of equal height (e.g. magnetic bubble inside a circular platelet in the limit of infinite anisotropy). Numerical results for the demagnetizing factors of massive and hollow cylinders and the mutual magnetizing factors of two coaxial cylinders are tabulated. These tables can also be used to determine the exact values of the self- and mutual inductances of two coaxial single-layer coils of given geometry. Es werden Formeln vorgelegt für die magnetostatische Energie und die Entmagnetisierungsfaktoren von zwei homogen magnetisierten koaxialen Zylindern derselben Höhe (z. B. magnetische Bubbledomäne innerhalb einer kreisförmigen Platte für den Grenzfall unendlicher Anisotropie). Numerische Resultate für die Entmagnetisierungsfaktoren von massiven und hohlen Zylindern und die gegenseitigen Magnetisierungsfaktoren von zwei koaxialen Zylindern werden tabelliert. Die Tafeln können auch für die Berechnung der genauen Werte der Selbst- und gegenseitigen Induktionen von zwei koaxialen Solenoiden der vorgelegten Geometrie benutzt werden.