Effect of electric field on NMR spectra in centroantisymmetric antiferromagnets

A symmetry approach is used to study the influence of electric field E on t he NMR frequency spectrum of antiferromagnets of the rhombohedral (Cr2O3) a nd tetragonal (e.g., the Fe2TeO6 trirutiles) systems exhibiting a linear ma gnetoelectric (ME) effect. The latter originates from the presence in their magnetic structure of an antisymmetry center (1) over bar'. It is shown th at besides the trivial effect of E on the NMR frequency through the total m agnetization induced by the ME phenomenon, there also exists an independent mechanism of a direct action of electric field on the local field at the n uclei, which can, in particular, produce an additional NMR frequency splitt ing. The dependence of this effect on the exchange magnetic structure and o rientational state is considered. (C) 2000 MAIK "Nauka/Interperiodica".