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Weak exchange and dimensionality : EPR of CaCuxCdx-1(H3C2O2)4 ·6H2O

1977; Elsevier BV; Volume: 25; Issue: 2 Linguagem: Inglês

10.1016/0022-2364(77)90024-5

1557-8968

R. M. Gaura, Richard D. Adams, D D'Avignon, Gerald F. Kokoszka, P. Szydlik,

Electron Spin Resonance Studies

Abstract A room-temperature EPR study of CaCu x Cd 1-x (H 3 C 2 O 2 ) 4 for 1⩾ x ⩾ 0.9 revealed no dramatic change in linewidth as Cd 2+ was incorporated into the lattice. The analysis of these results is consistent with the exchange field being less than or of the same order of magnitude as the dipolar and hyperfine fields but does not rule out one-dimensional behavior. A study in the ab plane of the x = 1 end member revealed a change in both linewidth and lineshape with angle. A simple model incorporating a Gaussian form for the electronic time-correlation function is shown to provide a semiquantitative account of these observations. Furthermore, the value for J derived from the lineshape analysis in this plane is somewhat smaller than but in order-of-magnitude agreement with the value derived from low-temperature magnetic susceptibility studies.