Ion exchange properties of β-eucryptite (LiAlSiO4): EPR investigation on copper-doped single crystals |
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Authors: | Jean-Louis Berchot Daniel Vivien Didier Gourier Jeanine Thery Robert Collongues |
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Institution: | Laboratoire de Chimie Appliquée de l''Etat Solide, L.A. 302, ENSCP 11, rue P. et M. Curie, 75231, Paris Cedex 05, France |
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Abstract: | Investigation of the ion exchange properties of β-eucryptite (LiAlSiO4) single crystals indicates that it is impossible to substitute Li+ by other bigger univalent cations such as Na+, K+, or Ag+. On the contrary, Li+ exchange by bivalent cations, Cu2+ or Mn2+, is very easy. For a general orientation of the crystal with respect to the magnetic field, the EPR spectrum of Cu2+ ions in β-eucryptite consists of 12 sharp lines partially superimposed on a broad line. The sharp lines are attributed to isolated copper ions in the conducting channels. Cu2+ lies in sixfold coordinated Li″ sites, but not in the fourfold coordinated Li″ sites. The corresponding spin Hamiltonian parameters at T = 140 K are found to be: gx = 2.362, gy = 2.340, gz = 1.990; ∥Ax∥ = 85 × 10?4cm?1, ∥Ay∥ = 71 × 10?4cm?1, ∥Az∥ = 203 × 10?4 cm?1. The broad line is attributed to clusters of Cu2+ located in neighboring Li″ sites. |
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