Inhomogeneous Magnetoelectric Effect on Defect in Multiferroic Material: Symmetry Prediction

Inhomogeneous magnetoelectric effect in magnetization distribution heterogeneities (0-degree domain walls) appeared on crystal lattice defect of the multiferroic material has been investigated. Magnetic symmetry based predictions of kind of electrical polarization distribution in their volumes were used. It was found that magnetization distribution heterogeneity with any symmetry produces electrical polarization. Results were systemized in scope of micromagnetic structure chirality. It was shown that all 0-degree domain walls with time-noninvariant chirality have identical type of spatial distribution of the magnetization and polarization.Comment: submitted to IOP Conference Series: Materials Science and Engineerin

Magnetoelastic effects in low-dimensional magnetic systems

We consider a new realization of magnetoelastic interactions in low-dimensional magnetic systems. We show that low-dimensional spin systems are unstable with respect to the spontaneous appearance of alternating distortions of the positions of the three-dimensional nonmagnetic atoms (ligands), that surround the magnetic ions. Those distortions are supplemented by the spontaneous onset of alternating effective g factors of the magnetic ions in the phase with short-range interactions. We discuss the possibility of observing the effect in an uniform external magnetic field, which in the situation considered produces both magnetization and staggered magnetization of the magnetic subsystem. The connection of the proposed theory with recent experiments on effectively low-dimensional magnetic systems (organic spin chains, heavy-fermion compounds, rare-earth molybdates) is discussed

Electrically active magnetic excitations in antiferromagnets (Review Article)

The magnetic resonance operation by electric field is highly nontrivial but the most demanding function in the future spin-electronics. Recently observed in a variety of multiferroics materials named the collective electrically active magnetic excitations, frequently referred to as “electromagnons”, reveal a possible way to implement such a function. Experimental advances in terahertz spectroscopy of electromagnons in multiferroics as well as related theoretical models are reviewed. The earlier theoretical works, where the existence of electric-dipole active magnetic excitations in antiferro- and ferrimagnets with collinear spin structure has been predicted, are also discussed. Multi-sublattice magnets with electrically active magnetic excitations at room temperature give a direct possibility to transform one type of excitation into another in a terahertz time-domain. This is of crucial importance for the magnon-based spintronics as only the short-wavelength exchange magnons allow the signal processing on the nanoscale distance