Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 29: Posters II

DY 29.16: Poster

Donnerstag, 29. März 2012, 17:00–19:00, Poster A

Mixed Ising ferrimagnets with next-nearest neighbour couplings on square lattices — •Walter Selke¹ and Cesur Ekiz² — ¹Institut für Theoretische Physik der Phasenübergänge, RWTH Aachen — ²Department of Physics, Adnan Menderes University, Aydin

We study Ising ferrimagnets on square lattices with antiferromagnetic exchange couplings between spins of values S=1/2 and S=1 on neighbouring sites, couplings between S=1 spins at next--nearest neighbour sites of the lattice, and a single--site anisotropy term for the S=1 spins. Using mainly ground state considerations and extensive Monte Carlo simulations, we investigate various aspects of the phase diagram, including compensation points, critical properties, and temperature dependent anomalies. In contrast to previous belief, the next--nearest neighbour couplings, when being of antiferromagnetic type, may lead to compensation points. W. Selke and C. Ekiz, J. Phys. C: Condensed Matter 23, 496002 (2011); W. Selke and J. Oitmaa, J. Phys. C: Condensed Matter 22, 076004 (2010)