Correlation between exchange bias and pinned interfacial spins

Using x-ray magnetic circular dichroism, we have detected the very interfacial spins that are responsible for the horizontal loop shift in three different exchange bias sandwiches, chosen because of their potential for device applications. The "pinned" uncompensated interfacial spins constitute only a fraction of a monolayer and do not rotate in an external magnetic field since they are tightly locked to the antiferromagnetic lattice. A simple extension of the Meiklejohn and Bean model is proposed to account quantitatively for the exchange bias fields in the three studied systems from the experimentally determined number of pinned moments and their sizes.     

Einfaches Modell für monoatomare klassische Flüssigkeiten

A simple approximation for the conditional time-dependent pair distribution functionP(r′t ¦ rt) is proposed. With this approximation the van Hove-correlation-functionG _d (rt) is computed and compared with Ludwig's¹ computer results for liquid A1. Then we determine the velocity autocorrelationfunction ψ(t) under special assumptions for the particle motion. That function is compared with Rahman's² computer results for liquid Ar.     

Quasiparticle density of states in the threedimensional Hubbard model

Quasiparticle densities of states are investigated for the threedimensional Hubbard model in the limit of strong coupling I >Δ (Δ = bandwidth) and for temperatures T → 0 by using the “method of spectral moments”. The densities of states depend on (i) the lattice structure, (ii) the band occupation and (iii) the magnetization of the system. Therefore these functions are evaluated for s.c.-, b.c.c.- and f.c.c.-lattices for some typical band occupations, and thereby first of all the influence of the magnetization is discussed.