Seminários

Event

Title:: D. Braithwait: (p,T,H) Phase Diagrams of Heavy Fermions
When:: 13.12.2011 11.00 h
Where:: Matéria Condensada Teórica - Niterói
Category:: Seminários

Description

(p,T,H) Phase Diagrams of Heavy Fermion Systems

Daniel Braithwaite (Grenoble - França)

Experiments using the combination of low temperature, high magnetic field and highpressure are essential to explore and understand the rich landscape of competing groundstates that appear in Heavy Fermion systems. Especially in the field of high pressure, recentinstrumental developments in the SPSMS and elsewhere have opened new prospects. In particular the implementation of resistivity, a.c. calorimetry and a.c. susceptibility in thediamond anvil cell opens up a much larger available pressure range for these measurements, in excellent hydrostatic conditions, with in addition the possibility to tune the pressure in-situat low temperature. I will present these instrumental advances and illustrate them with somerecent results on the interplay of superconductivity and magnetism, notably in cerium anduranium compounds. I will then discuss what we can learn from the comparison betweencerium compounds, and their ytterbium based “hole” analogues, and present recent results onseveral ytterbium systems, including the recent discovery that the magnetic order whichoccurs under high pressure in YbCu2Si2 is ferromagnetic[1]. This adds further evidence of aseemingly general trend towards ferromagnetism in ytterbium systems which could explainsome of the differences between Yb and Ce compounds.

References
1. A. Fernandez-Pañella, D. Braithwaite, B. Salce, G. Lapertot, and J.
Flouquet, Phys. Rev. B 84, 134416 (2011).

Local: antiga sala da biblioteca
Horário: 11h - terça-feira (13/12).