J. Kaczér

Experimental evidence of the magnetic moment of Bloch walls in garnet films

Abstract 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.

Domain period determination in CoCr films

Abstract Domain structures of two low coercivity ( H c / H k ≈ 0.02) and one medium coercivity ( H c / H k ≈ 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.

Domain observation of a CoCr film by the colloid-sem method

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.

Magnetization reversal and Bloch lines in bubble domain walls

Abstract 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.