6533b836fe1ef96bd12a0835

RESEARCH PRODUCT

Order-disorder evolution in solid solutions of the NLO material KTiOPO : K Rb TiOPO and K Rb TiOPO in the temperature range 293-973 K

Bertrand MénaertM. JanninP. DelarueClaude LecomteG. Marnier

subject

DiffractionMaterials scienceSolid-state physicsAnharmonicityAnalytical chemistrychemistry.chemical_elementAtmospheric temperature rangeCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsIonRubidiumchemistryIonic conductivitySolid solution

description

K0.88Rb0.12TiOPO4 and K0.465Rb0.535TiOPO4 solid solutions of the potassium titanyl phosphate (KTiOPO4, space group Pna21) family, are described at 293, 473, 673, 873 and at 973 K. Their high resolution structures are obtained by using accurate single-crystal X-ray diffraction techniques at high resolution, (sin A-1. Large anharmonic motion of alkaline ions increasing with temperature allows the evolution of the rubidium and potassium ions repartition in the two alkaline sites versus temperature. To describe this motion inducing ionic conductivity phenomenon and to determine accurately the order-disorder evolution, two alkaline site refinement models are developed and discussed. A thermodynamic model, which uses a barrier-potential model, is also developed to specify the different interactions operating in the order-disorder evolution, and more generally interactions between alkaline ions and the framework.

https://doi.org/10.1007/s100510050124