Science / Technology - Colloquium
Monday, March 23, 2009
4:00 PM-5:00 PM
Olin Hall
107
URu2Si2 is a heavy-fermion compound the low temperatures and high magnetic fields phase diagram of which is characterized by the presence of a Hidden-Order phase below 17 K up to 36 T, multiple ordered phases below 7 K between 36 and 42 T and itinerant electron metamagnetism (IEMM):
(1)* Rhenium doping of URu2Si2 yields unusual magnetic and electronic behaviors at low temperatures with a smearing of the Hidden-Order at x ~ 0.10, Non Fermi Liquid behavior from x ~ 0.15 and weak ferromagnetism from x ~ 0.30. In order to address the effects of Re doping on the multiple field-induced ordering and on the IEMM, we measured the magnetization and magnetoresistance properties of URu2-xRexSi2 single-crystals in pulsed magnetic fields up to 65 T allowing it to determine a comprehensive (T, B, x) phase diagram. The field-induced ordering is suppressed at x = 0.05, the Heavy-Fermion (HF) state and the IEMM at x = 0.35. The suppression of the HF state is found to condition the suppression of the IEMM and the emergence of the ferromagnetism.
(2)** Rhodium doping yields the growing of a single ordered phase, so called phase II, below 10 K at fields above 27 T and complete suppression of the Hidden order phase. In order to get some clues about the nature of the order parameter in phase II, we measured magnetostriction and thermal expansion on a URu1.92Rh0.04Si2 single-crystal using a capacitive dilatometer. Important dilation effects are evidenced in the underlying Fermi liquid outside phase II as observed previously in the 4f analog compound CeRu2Si2 as well as anisotropic and significant length changes in phase II.
Cost: FREE
Suggested Audiences: College
E-mail:
izabela@wpi.edu
Phone: 508-831-5249
Last Modified: March 17, 2009 at 2:42 PM
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