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Magnetic Order and Search for Magnetoelectric Effect in Metal-Organic Compounds: 2D Cu-Cl / Ethyl-Ammonium System and 3D Mn-Oxalate Network as Examples

Magnetoelectric multiferroics are materials in which both the magnetic and electric orders appear, and coupling between these orders comes in many varieties, still being under intensive research. It is known that some kinds of non- collinear spin orders or nano-magnetic inhomogeneities can produce also the electric polarization and/or magnetoelectric effect. Here we present the magnetic behaviour of two metal- organic compounds. Compound CuCl4(C2H5NH3)2 consists of the magnetic Cu-Cl layers separated with layers of ethyl-ammonium cations. Such arrangement of the cations leads to the ferroelectric state below 250 K.[1] Long range magnetic order below 10.5 K is determined with the ferromagnetic interactions within the Cu-Cl plane and much weaker antiferromagnetic interplane interaction. Till now, we observed the influence of electric field onto magnetization only at the high temperatures of 330 K, 356 K and 364 K, where the magnetoelectric effect is mediated via coupling to the structural changes. Novel heterometallic coordination polymer {; ; ; [Cu(C10H8N2)3][Mn2(C2O4)3]·H2O}; ; ; n showed antiferromagnetic-like transition at 12.8 K.[2] However, the spins are not ordered antiparallel, but from analysis of the magnetization it follows that the spins are canted, producing thus the weak ferromagnetism. This is motivating for searching of the magnetoelectric phenomena. Both examples are suitable for tuning and design of systems in favour of magnetoelectric multiferroic state. This work is supported by the Croatian Science Foundation under the project FerMaEl (UIP-2014-09- 8276). [1] Kundys, B. et. al., Physical Review B 81 (2010) 224434 [2] Jurić M. et.al., Dalton Transactions 44 (2015) 20626A

magnetic order, magnetoelectric effect, multiferroics, metalorganic complexes

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