Published online by Cambridge University Press: 26 February 2011
As a consequence of the unusual nature of plutonium's electronic structure, point- and extended-defects are expected to, and do exhibit extraordinary properties. Low temperature magnetic susceptibility measurements on Pu and fcc-Pu(Ga) show that the magnetic susceptibility increases as a function of time, yet upon annealing the specimen returns to its initial magnetic susceptibility. This excess magnetic susceptibility (EMS) arises from the alpha-decay and U recoil damage cascades which produce vacancy and interstitials as point and extended defects. The temperature of the first annealing stage defines a temperature (<35K) below which we are able to characterize the time and temperature evolution of the accumulating damage cascades as being a saturation function. The temperature dependence of the EMS is well described by a time independent, Curie-Weiss curve arising from a volumetric region surrounding each U damage cascade. This saturation picture also leads directly to a determination of the microscopic volume of the specimen that is affected by the frozen-in damage cascade. For our measurements in δ-Pu we calculate a diameter of the magnetically affected volume of ∼250Å per damage cascade. This should be compared with an estimated volume that encloses the damage cascade itself (determined from molecular dynamics) of ∼100 Å. Hence, the ratio of these volumes is ∼8. The observed anomalous magnetic behavior is likely a consequence of the highly correlated nature of the electrons. Similarities with defects in hole-doped superconductors suggest a general phenomenon in strongly correlated electron systems, of which Pu may be a particularly unusual or special example.
To send this article 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 sending to your Kindle. 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 this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.
To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.