Berlin 2012 – scientific programme

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KR: Fachgruppe Kristallographie

KR 2: Joint Session "Multiferroics I - Junctions and Thin Films / Magnetoelectric Coupling" (MA jointly with DF, DS, KR, TT), Organization: Manfred Fiebig (ETH Zürich)

KR 2.8: Talk

Monday, March 26, 2012, 11:45–12:00, EB 301

Microscopic Mechanisms for Magnetoelectric Effect in LiMPO₄ (M=Mn,Fe,Co,Ni) — •Andrea Scaramucci, Eric Bousquet, and Nicola Spaldin — Materials Theory, Department of Materials, ETH Zurich, Zurich, Switzerland

We theoretically investigate the microscopic mechanisms leading to the linear magnetoelectric effect in the LiMPO₄ series. This is of particular interest since some of its constituents possess toroidal moments and shows large magnetoelectric effect.

By using symmetry analysis we obtain the microscopic couplings between spins and electric polarization responsible for each component of the magnetoelectric tensor. Furthermore, we identify couplings with exchange-strictive and relativistic origin. By using ab initio calculation and by enforcing numerous non collinear spin configurations we extract the strength of these couplings together with the exchange coupling constants. We use mean field approximation and Monte Carlo simulation to calculate the temperature evolution of magnetoelectric tensor. Our calculations explain the features of the temperature dependence found in experiments.