A New Unconventional Antiferromagnet, Yb${}_3$Pt${}_4$

Abstract

We report the synthesis and basic properties of single crystals of a new binary compound, Yb${}_3$Pt${}_4$. The Yb ions in this compound are fully trivalent, and heat capacity measurements show that the crystal field scheme involves a doublet ground state, well separated from the excited states, which are fully occupied above $\sim$ 150 K. The heat capacity displays a large, weakly first order anomaly at 2.4 K, where a cusp is observed in the magnetic susceptibility signalling the onset of antiferromagnetic order. The entropy associated with this order is the full Rln2 of the doublet ground state, however the magnetic susceptibility in the ordered phase is dominated by a large and temperature independent component below the Neel temperature. The heat capacity in the ordered state originates with ferromagnetic spin waves, giving evidence for the inherently local moment character of the ordered state. The electrical resistivity is unusually large, and becomes quadratic in temperature exactly at the Neel temperature. The absence of analogous Fermi liquid behavior in the heat capacity and the magnetic susceptibility implies that Yb${}_3$Pt${}_4$ is a low electron density system, where the Fermi surface is further gapped by the onset of magnetic order.

8 pages, 9 figures

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Cited by in corpus (5)

• Magnetic field tuning of antiferromagnetic Yb${}_3$Pt${}_4$
• Determination of the magnetic structure of Yb3Pt4: a k=0 local-moment antiferromagnet
• High temperature antiferromagnetism in Yb based heavy fermion systems proximate to a Kondo insulator
• Localized moments and the stability of antiferromagnetic order in Yb3Pt4
• Magnetic transition and spin fluctuations in the unconventional antiferromagnetic compound Yb3Pt4