Counter-complementarity control of the weak exchange interaction in a bent {Ni(ii)3} complex with a μ-phenoxide-μ-carboxylate double bridge

We report a combined computational and experimental study of a weak exchange interaction in a bent {Ni(ii)3} complex controlled by counter-complementarity.

Фаза Имри-Ма в нанокристаллическом ферромагнетике

A possibility of appearing a disordered Imry–Ma state induced by fluctuations of the anisotropy easy axis direction in a nanocrystalline sample in the case of a weak exchange interaction between crystallites has been studied. A phase diagram of the system has been built in variables “the characteristic crystallite size–the exchange integral of the intercrystallite interaction.” The characteristic value of statistic fluctuations of the crystallographic anisotropy has been estimated, and the dependences of the coercive field on the crystallite size have been found for systems of various space dimensions.

Synthesis, crystal structure and magnetism of [Cu(cyclam)Ni(NCS)4(H2O)2]n

Abstract[Cu(cyclam)Ni(NCS)4(H2O)2]n(1) (cyclam = 1,4,8,11-tetraazacyclodecane) exhibits bent 1D crystal structure in which paramagnetic Cu(II) and Ni(II) atoms are linked by bridging μ2-NCS- ligands. The Cu(II) atom exhibit tetragonally elongated hexacoordination in the 4+2 form with one tetradentate macrocyclic cyclam ligands placed in the equatorial plane while the axial positions are occupied by S atoms from bridging NCS- ligands. The Ni(II) atom in NiN4O2donor set is deformed octahedrally coordinated by four isothiocyanato ligands among which two in trans positions are bridging in nature; additional aqua ligands occupy the remaining two positions in trans arrangement. Weak hydrogen bonding interactions of the O-H···S type links the formed chains into 3D supramolecular structure. The magnetism of 1 is dominated by a sizable single-ion anisotropy DNi/hc = +7.49 cm-1along with a weak exchange interaction of the ferromagnetic nature.