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1

An impact of the state and type of surface layer on magnetic properties of Cu/Ni and Ni/Cu multilayers

Gągorowska B., Duś-Sitek M., Nabiałek M.

Optica Applicata

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2009

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Vol. 39, nr 4

839-844

EN

This paper presents the results of investigation of magnetic properties in Cu/Ni multilayer systems. Based on the investigation of Ni/Cu and Cu/Ni systems with different thickness of magnetic and non-magnetic layers it was proved that the presence of ferromagnetic (F-F) and antiferromagnetic (A-F) exchange couplings depends on the quality of layers in artificial superlattice and on the state and type of free surface, superlattice structure and its roughness.

2

Synthesis and Magnetism of Ferromagnetically Coupled {Cu II 3 Cr III] Heterotetranuclear Complexes with N,N'-Bis(aminoalkyl)oxamidatocopper(II)

Li Y., Yan C., Xu G., Zhang G., Sun W.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 9

1415-1424

EN

The strategy of "complex as ligand" allowed us to synthesize two new _-oxamido- bridged copper(II)-chromium(III) heterotetranuclear complexes formulated as [Cu3(oxae)3Cr](ClO4)3 (1) and [Cu3(oxpn)3Cr](ClO4)3 (2), where oxae and oxpn represent N,N_-bis(2-aminoethyl)oxamido and N,N_-bis(3-aminopropyl)oxamido dianions, respectively. Based on elemental analyses, molar conductivity and magnetic moment (room-temperature) measurements, IR, ESR and electronic spectral studies, these complexes are proposed to have oxamido-bridged structures consisting of three copper(II) ions and a chromium(III) ion, in which the chromium(III) ion has an octahedral environment and the three copper(II) ions have a square-planar environment. The two heterotetranuclear complexes were further characterized by variable-temperature magnetic susceptibility (3~300 K) measurements and the magnetic data have been used to deduce the indicated heterotetranuclear structure. The results derived from least-squares fit of the experimental data have confirmed the ferromagnetic interaction between the adjacent copper(II) and chromium(III) ions through the oxamido-bridge within each molecule. On the basis of the spin Hamiltonian operator, H=-2J(S Cu1 . S Cr+S Cu2 . S Cr + S Cu3 . S cr) , the magnetic analyses were carried out for the two copper(II)-chromium(III) heterotetranuclear complexes and the spin-coupling constants (J) were evaluated as +13.98 cm-1 for (1) and +12.65 cm-1 for (2). The results indicate that the bridging oxamido should be able to transmit ferromagnetic interaction in the strict orthogonality [Cu3 IICrIII] system. The influence of the symmetry of the magnetic orbitals on the nature of the magnetic interaction between the paramagnetic centers is preliminarily discussed.

3

Synthesis and Magnetic Studies of Copper(II)-Lanthanide(III) Heterobinuclear Complexes Bridged by N,N'-Bis[3-(dimethylamino)propyl]oxamido

Li Y., Yan C., Wu Z., Zhu C.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 1

37-46

EN

Ten new copper(II)-lanthanide(III) heterobinuclear complexes bridged by N,N'-bis[3- (dimethylamino)propyl]oxamido dianions (dmoxpn) and end-capped with 2,2'-bipyridine (bpy), namely, Cu(dmoxpn)Ln(bpy)2(NO3)3 (Ln = La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb), have been synthesized and characterized by elemental analyses, molar conductivity measurements, and spectroscopic (IR, UV, ESR) studies. The Cu(dmoxpn)Gd(bpy)2(NO3)3 complex was further characterized by variable-temperature magnetic susceptibility (4.2~300 K) measurements and the magnetic data have been also used to deduce the indicated heterobinuclear structure. The results derived from least-squares fit of the experimental data have confirmed that the adjacent copper(II) and gadolinium(III) ions through the oxamido-bridge in the complex are ferromagnetically coupled with the exchange integral J(Cu-Gd) = +8.59 cm-1. A plausible mechanism for the ferromagnetic coupling between gadolinium(III) and copper(II) is discussed in terms of spin-polarization.

4

Novel Ferromagnetic Coupling Dicopper(II), Antiferromagnetic Dicobalt(II) and Dimanganese(II) Complexes with 3-Nitro-phthalato as Bridging Ligand: Synthesis, Spectrum and Magnetism

Ma S. L., Zhang L. Z., Lu L. L., Tang M. Y.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 4

511-517

EN

Novel copper(II), cobalt(II) and manganese(II) binuclear complexes have been synthesized, namely [Cu2(3-NO2-phth)(phen)4](ClO4)2 and [M2(3-NO2-phth)(phen)4(H2O)2](ClO4)2, whereM=Co orMn, phen = 1,10-phenanthroline and 3-NO2-phth denotes 3-nitro-phthalate dianion. Magnetic susceptibility measurements between 4.2-300 K (or 77-300 K) demonstrate a ferromagnetic interaction between two copper(II) ions in the Cu-Cu complex, and a weak antiferromagnetic interaction between the metal ions in Co-Co and Mn-Mn complexes. Based on spin Hamiltonian operator, _H = -2J _ S1_ _ S2 (S1=S2 = 1/2, S1=S2 = 3/2 or S1 = S2 = 5/2), J is found to be equal to +5.26 cm-1, -1.72 cm-1 and -0.62 cm-1 for the Cu-Cu, Co-Co and Mn-Mn complexes, respectively