Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 79: Correlated Electrons - Poster Session
TT 79.9: Poster
Wednesday, April 2, 2014, 15:00–19:00, P2
Effect of Ni-doping on the geometrically frustrated heavy-fermion system CePdAl — •Stefan Lucas1, Zita Huesges1, Sarah Woitschach1, Oliver Stockert1, Veronika Fritsch2, and Hilbert von Löhneysen2 — 1Max Planck Institute CPfS, Dresden, Germany — 2Karlsruhe Institute of Technology, Karlsruhe, Germany
The heavy-fermion compound CePdAl is an interesting system for investigations of quantum criticality in combination with geometric magnetic frustration, which arises from the hexagonal crystal structure of the system. In zero magnetic field, the Néel temperature of 2.7 K can be reduced by doping nickel on the palladium sites. At a doping level of about 14 %, the Néel temperature becomes zero and a quantum critical point is reached. To follow the magnetic order upon nickel doping and investigate the effect of magnetic frustration closer to the quantum critical point, we performed extensive heat capacity measurements on a 5 % Ni-doped single crystal. CePd0.95Ni0.05Al orders below TN ≈ 1.85 K via a second-order phase transition in contrast to the weakly first-order transition in pure CePdAl. Our measurements reveal for CePd0.95Ni0.05Al a critical magnetic field BC ≈ 3 T (B ∥ c, T → 0) to fully suppress the antiferromagnetic phase. We will discuss the resulting magnetic B−T phase diagram and compare it with the parent compound CePdAl.