We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 03 May 2011
Here we reconcile the thermodynamic quantity ‘order parameter’ and the geometrical quantity ‘spontaneous strain’. Their temperature dependencies may follow each other but do not necessarily do so. Some symmetry arguments help to identify possible non-linearities. The coupling between the order parameter and the spontaneous strain produces an important physical effect: elastic softening of the crystal. Some simple algebra is needed to quantify the behaviour of the elastic constants. The reader is encouraged to work through this chapter because it illustrates some arguments which will be used repeatedly later on.
So far we have introduced the order parameter as the thermodynamic quantity which describes the phase transition and the macroscopic spontaneous strain as a convenient physical parameter which serves to characterise the change of shape of a crystal (or of the crystallographic unit cell for the structural or spontaneous strain). In some crystals, the order parameter and the spontaneous strain are simply proportional to each other. In most crystals this is not the case, however, and we must now explore rather carefully the possible correlations between the thermodynamic order parameter, Q, and the structural spontaneous strain, es. The general scope of this treatment is the coupling theory (e.g. Salje and Devarajan 1986, Achiam and Imry 1975, Gufan and Larin 1980, Imry 1975, Oleksy and Prysztawa 1983). It is based on the assumption that the crystal is in thermodynamic equilibrium with a surrounding heat bath and that its structural state is dictated by the condition that no structural variables can be changed without loss of energy.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.
