Domain wall theory and exchange stiffness in Co/Pd multilayers

The stripe model of domain structure in multilayers is studied by micromagnetic simulation. The results indicate a strong reduction of the effective domain wall energy (by dipolar effects). Domain width measurements on sputtered Co/Pd multilayers are compared with the theory. The estimated exchange stiffness is comparable with that of bulk Co. The effects of interface roughness and of interlayer exchange are discussed

Magnetism and Electronic Structure in ZnFe2_2O4_4 and MnFe2_2O4_4

Density functional calculations are used to study magnetic and electronic properties of the spinel ferrites, ZnFe$_2$O$_4$ and MnFe$_2$O$_4$. Correct magnetic orderings are obtained. ZnFe$_2$O$_4$ is predicted to be a small gap insulator in agreement with experiment. MnFe$_2$O$_4$ is found to be a low carrier density half-metal in the fully ordered state. However, strong effects on the electronic structure are found upon partial interchange of Fe and Mn atoms. This indicates that the insulating character may be due to Anderson localization associated with the intersite Mn-Fe disorder.Comment: 3 pages, submitted to mmm01 conferenc

Complement as an Endogenous Adjuvant for Dendritic Cell-Mediated Induction of Retrovirus-Specific CTLs

Previous studies have demonstrated the involvement of complement (C) in induction of efficient CTL responses against different viral infections, but the exact role of complement in this process has not been determined. We now show that C opsonization of retroviral particles enhances the ability of dendritic cells (DCs) to induce CTL responses both in vitro and in vivo. DCs exposed to C-opsonized HIV in vitro were able to stimulate CTLs to elicit antiviral activity significantly better than non-opsonized HIV. Furthermore, experiments using the Friend virus (FV) mouse model illustrated that the enhancing role of complement on DC-mediated CTL induction also occurred in vivo. Our results indicate that complement serves as natural adjuvant for DC-induced expansion and differentiation of specific CTLs against retroviruses

Stripe and bubble domains in cocr films

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Jahn-teller domains and magnetic domains in Mn2FeO4

Elastic (Jahn–Teller) domains and magnetic domains in the tetragonal spinel Mn2FeO4 were studied using X-ray double-crystal topography, X-ray diffractometry and the colloid-SEM method. The Jahn–Teller domains of the measured samples are tetragonal with the [0 0 1] c-axis alternating perpendicularly (thick domains) and parallel (thin domains) with respect to the growth direction of the specimens. Boundary interfaces are of the (1 1 0) type consistent with the cubic spinel system. A complex magnetic domain structure is discussed in relation with the crystallographic orientation of the Jahn–Teller domains

The field dependence of the domain period in CoCr films

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

Kerr Rotation and XPS Spectra of Co/Pd Multilayers

The influence of the surface conditions of a series of the polycrystalline Co/Pd multilayers on the spectral dependence of the polar Kerr rotation, θk, was studied. Starting from low values, |θk| was found to increase towards short wavelengths, reaching 0.2 degree at the blue region. Using angular resolved photoelectron spectroscopy the oxidation states and the binding conditions of Co and Pd nearest surface layers were examined