title: Study of negative thermal expansion and shift in phase transition temperature in Ti4+- and Sn4+-substituted ZrW2O8 materials.
abstract: The negative-thermal-expansion material ZrW(2)O(8) is known to undergo an order-disorder phase transition which affects its expansion behavior. In this study, Ti(4+) and Sn(4+) are examined as possible substituting ions for the Zr(4+) position in ZrW(2)O(8). This substitution leads to a decrease in cell parameters, as the ionic radii of the substituents are smaller than the Zr(4+) ionic radius. A remarkable decrease in transition temperature is noticed. DSC is used to quantify the enthalpy and entropy changes during the phase transition in order to reveal the mechanisms behind this decrease. It is shown that the strength of the M-O bond plays an important role, as it is a partner in the rigid unit mode motion and the order-disorder transition mechanism.
authors: Department of Inorganic and Physical Chemistry, Building S3 Ghent University Krijgslaan 281, 9000 Ghent, Belgium. Klaartje.DeBuysser@Ugent.be
authors: Klaartje De
authors: KD
authors: Buysser
authors: Isabel Van
authors: IV
authors: Driessche
authors: Bart Vande
authors: BV
authors: Putte
authors: Paul
authors: P
authors: Vanhee
authors: Joseph
authors: J
authors: Schaubroeck
authors: Serge
authors: S
authors: Hoste