Phase Diagram near a Quantum Critical point in ultra-pure Sr3Ru2O7.

R. A. BORZI; S. A. GRIGERA; R. S. PERRY; KIKUGAWA, N.

Windsor, Inglaterra

Otro; Third Windsor Summer School on Condensed Matter Theory: Field Theory of Quantum Coherence, Correlations and Mesoscopics; 2004

Lancaster University

Cristal disorder may play a major role in changing the nature or hiding the actual ground state of the layered ruthenates oxides. The single-layered Sr2RuO4, best known for its triplet superconductivity, has been a good example of this behaviour. The same is true for the bilayered compound Sr3Ru2O7, which changed from a ferromagnetic metal to a paramagnetic Fermi liquid when improving its purity. A metamagnetic transition at $approx$ 7 T in these purer samples has lead to the understanding of a new type of quantum criticality with no associated symmetry breaking. What would happen within the region dominated by diverging quantum critical fluctuations if the purity levels of Sr3Ru2O7 single-crystals were improved further? Supported by susceptibility, magnetostriction, transport, magnetisation and quantum oscillations measurements we will show the new phase diagram near the quantum critical point.