arXiv subjects

F. Süss

Publications and source records attributed to F. Süss.

5 recordsLinked to original sources

arXiv1996

Exchange coupling and magnetization profiles of binary and ternary magnetic multilayers

Within a spin-polarized LMTO approach in the Atomic-Sphere approximation we calculate ab initio the magnetic properties of various binary and ternary multilayers composed of Fe, Co, Ni, Cr, V and Cu. The emphasis lies on the indirect exchange interaction of the magnetic sandwiches across the antiferromagnetic or non-magnetic spacers, and on the profiles of the intrinsic resp. induced magnetic moments. Among other results we find: (i) that Ni is very sensitive on its neighborhood and that (ii) at the interface to Fe, V gets almost as strongly polarized as Cr, whereas in the interiour layers, the V sandwich remains nonpolarized.

cond-mat↗

arXiv1996

First principles studies of modulated Co/Cu superlattices with strongly and weakly exchange biased Co-monolayers

First-principles calculations have been performed in order to determine effective exchange integrals between {\it strongly} and {\it weakly} exchange-coupled Co monolayers in certain modulated periodic $CoCu_2/CoCu_n$-type superlattices with three non-equivalent Co planes, which have not yet been studied hitherto. For $3\le n\le 6$ we find that the two non-equivalent exchange integrals have opposite signs, i.e.~the strong coupling is antiferromagnetic and the weak coupling ferromagnetic, and differ for $n\ne 4$ from each other by one order of magnitude. It is shown that the results depend on the system as a whole and could not be obtained from separate parts. Finally we suggest that ''spin valve'' systems of such kind should be considered when trying to obtain good magneto-resistance together with low switching-fields.

cond-mat↗

arXiv1995

First-principles studies of modulated Co/Cu superlattices with strongly and weakly exchange-biased Co-monolayers leading to a ferrimagnetic ground state

First-principles calculations have been performed in order to determine effective exchange integrals between strongly and weakly exchange-biased Co monolayers in the modulated CoCu$_2$/CoCu$_n$ superlattices. For $3\le n\le 6$ it has been found that the respective exchange integrals have opposite signs and differ for $n\ne 4$ from each other by one order of magnitude and for $n=4$ still by a factor of $\sim 1.7$. The obtained phase diagram, with all the relevant magnetic phases, shows that for the $n$-values considered, the ground state configuration is ferrimagnetic.

cond-mat↗

arXiv1995

Oscillatory Thickness Dependence of Magnetic Moments and interface-induced Changes of the Exchange Coupling in Co/Cu and Co-Ni/Cu Multilayers

We perform first-principles calculations for the three multilayer systems (100)-Co_1/Cu_n, -NiCo_2Ni/Cu_n and -Co_4/Cu_n, and find from a comparison x of the results for system 2 and 3 that amplitude and phase of the exchange coupling are sensitive to the magnetic-slab/nonmagnetic-spacer interface. Moreover, we observe that for the system 1 and 2 the averaged magnetic moment of the magnetic slab oscillates with the spacer thickness similarly as the exchange coupling.

cond-mat↗

arXiv1995

Numerical Studies on the Magnetism of Fe-Ni-Mn Alloys in the Invar Region

By means of self-consistent semi-empirical LCAO calculations we study the itinerant magnetism of (Fe_{0.65}Ni_{0.35})_{1-y} Mn_y alloys for y between 0 and 0.22 at T=0 K, neglecting only the transverse spin components. We find that the magnetic behaviour is quite complicated on a local scale. In addition to ferromagnetic behaviour, also metastable spin-glass-like configurations are found. In the same approach, using a direct numerical calculation by the Kubo-Formalism without any fit parameters, we also calculate the electrical conductance in the magnetic state and find that the $y$-dependence observed in the experiments is well reproduced by our calculations, except of an overall factor of rougly 5, by which our resistivities are too large.

cond-mat↗