Regensburg 2007 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 4: Internal Symposium “Order/Disorder versus/with Displacive Behaviour”

DF 4.2: Vortrag

Dienstag, 27. März 2007, 10:40–11:00, H11

High resolution NMR of phase transitions: experimental criteria for order/disorder vs. displacive behaviour — •Naresh Dalal — Florida State University and National High Magnetic Field Laboratory

Traditionally, phase transitions have been classified as of either `order-disorder' or `displacive' type. Recently, however, there has been increasing evidence that this classification should be reexamined, and that many systems that were considered as proto-types of order-disorder type, actually exhibit strong features indicating the role of `displacive' mechanism as well. We have found that among other techniques for probing this question, the modern high-field, high-resolution nuclear magnetic resonance (NMR) could prove to be perhaps the most sensitive and easily accessible method. This presentation will discuss the basics of this tenet, experimental details and recent data, with a conclusion that perhaps most such transitions involve both types of features, and should thus be reclassified as such.