Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 59: Correlated Electrons: Quantum-Critical Phenomena - Experiments
TT 59.2: Talk
Thursday, March 14, 2013, 15:15–15:30, H6
µSR investigations on the 4f-derived ferromagnetic quantum quantum critical system YbNi4(P1−xAsx)2 — •Rajib Sarkar1, Johannes Spehling1, Cornelius Krellner2, Hubertus Luetkens3, Chris Baines3, Manuel Brando4, Christoph Geibel4, and Hans-Henning Klauss1 — 1IFP, TU Dresden, D-01069 Dresden, Germany — 2Goethe University Frankfurt, D-60438 Frankfurt am Main, Germany — 3PSI, CH-5232 Villigen PSI, Switzerland — 4MPI-CPFS, D-01187 Dresden, Germany
Ferromagnetic quantum criticality (FMQC) is one central topic of research in strongly correlated electron systems. Despite adequate research so far there is no concrete evidence of FMQC. In this context, the recently discovered 4f-derived heavy fermion
FM metal YbNi4P2 with Tc =170 mK, a Kondo temperature TK=8 K and a very small ordered moment of ≈ 0.05 µB, deserves particular interest [1]. With 8 % As substitution at the P site,
Tc goes down to 28 mK and the Grüneisen ratio diverges as Γ(T)∝ T−0.22, evidencing the presence of FMQC.
For YbNi4P2, zero field µSR investigations prove static long range magnetic ordering [2] and the ordered moment is strongly suppressed with increasing As-substitution. For 8% As, µSR time spectra suggest that static ordering appears below 20 mK. Here, we present our recent µSR results for x ≤ 0.13 and discuss the dynamics of the quantum fluctutations at this ferromagnetic quantum critical point.
[1] New J. Phys. 13, 103014 (2011)
Phys. Rev. B 85, 140406 (2012)