Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)

MA 20.127: Poster

Dienstag, 28. März 2006, 15:15–19:15, P1

Second Harmonic Generation on NiO beyond the electric — •Georgios Lefkidis and Wolfgang Hübner — University of Technology of Kaiserslautern, Box 3049,

The discrete intragap states of both the bulk and (001) surface of NiO could be used with a four level ultrafast magnetic switching scenario [1]. For this a tool is needed, both to detect the magnetic state of the sample, and to monitor the process. Second harmonic generation (SHG) is a very well suited tool, for it couples linearly to the antiferromagnetic order parameter and can detect all NiO domains.

NiO is modelled as a doubly embedded cluster and its levels are obtained from ab-initio many-body theory. The discrete intragap d-states are obtained from the multiconfigurational complete active space method (MC-CAS), while the charge transfer states are computed employing the single excitation configuration - interaction technique with energy corrections from higher excitations [CIS(D)].

The second order susceptibility tensor is calculated beond the electric dipole approximation from first principles taking into account magnetic dipole and electric quadrupole transitions as well [2]. The dependence on the light polarization is given, as well as the effects of phonons within the frozen phonon approach, and the influence of nonlocalities. Finally the effect of spin-orbit coupling is discussed.

[1] R. Gómez-Abal, K. Satitkovitchai, O. Ney, and W. Hübner, Phys. Rev. Lett. 92, 227402, (2004)

[2] G. Lefkidis and W. Hübner, Phys. Rev. Lett. 95, 77401, (2005)