Emerging Magnetism Arising from Self-Damage in (alpha) and (delta)-Pu
As a consequence of the unusual nature of plutonium's electronic structure, point- and extended-defects are expected to, and do exhibit extraordinary properties[1]. 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 d-Pu we calculate a diameter of the magnetically affected volume of {approx} 250 {angstrom} per damage cascade. This should be compared with an estimated volume that encloses the damage cascade itself (determined from molecular dynamics) of {approx}100 {angstrom}. Hence, the ratio of these volumes is {approx}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.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 894789
- Report Number(s):
- UCRL-JRNL-217247; TRN: US0700316
- Journal Information:
- Materials Research Society Symposium Proceedings, vol. 893, N/A, March 1, 2006, pp. 0893-JJ04-03.1-11, Journal Name: Materials Research Society Symposium Proceedings, vol. 893, N/A, March 1, 2006, pp. 0893-JJ04-03.1-11
- Country of Publication:
- United States
- Language:
- English
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