%0 Conference Proceedings
%T Exchange coupling in spins quartet of dimeric polyoxoanions [M-4(H2O)(2)(GeW9O34)(2)](12-) (M = Mn2+, Cu2+)
%+ Groupe d'étude des semiconducteurs (GES)
%A Isber, S.
%A Tabbal, M.
%A Christidis, T.
%A Terki, Ferial
%A Charar, Salam
%< avec comité de lecture
%Z GES:05-055
%( JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
%B Joint European Magnetic Symposia (JEMS 04)
%C Dresden (GERMANY), France
%V 290
%P 985-988
%8 2004-09-05
%D 2004
%K magnetization
%K exchange coupling
%K EPR
%K spin clusters
%K CRYSTAL-STRUCTURE
%K MAGNETIC-PROPERTIES
%K CLUSTERS
%Z Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Conference papers
%X Magnetization and magnetic susceptibility of dimeric polyoxoanions [M-4(H2O)(2)(GeW9O34)(2)](12-) (M = Mn2+, Cu2+) were investigated using an isotropic exchange coupling model with two coupling constant (J and Y) within the spin quartet formed by M4O16 (M = Mn2+, Cu2+). The exchange couplings were found to be antiferromagnetic for both samples with the values (J/k(B) = -0.91 &PLUSMN; 0.04 K and J'k(B) = - 1.18 &PLUSMN; 0.02 K) and (J/k(B) = - 13.5 &PLUSMN; 0.5 K and J'/ k(B) = -66 &PLUSMN; 4 K) for the samples containing Mn2+ and Cu2+, respectively. Furthermore, X- and Q-Band powder electron paramagnetic resonance (EPR) measurements on the sample containing Cu2+ were investigated and the experimental spectra were simulated using a triplet spin state S = 1 and I = 3, and including a small axial distortion D term. This leads to spin-Hamiltonian parameters of: &VERBAR; D&VERBAR; = 0.44 &PLUSMN; 0.01 GHz, g&VERBAR;&VERBAR; 2.415 &PLUSMN; 0.005, g&BOTTOM; = 2.070 &PLUSMN; 0.005, A(ii) = (40 &PLUSMN; 1) G. © 2004 Elsevier B.V. All rights reserved.
%G English
%L hal-00539824
%U https://hal.science/hal-00539824
%~ CNRS
%~ UNIV-MONTP2
%~ GES
%~ UNIV-MONTPELLIER
%~ UM1-UM2