Crystal Structure and Magnetic Properties of the Breathing Kagome Ising Antiferromagnet Yb3Ni11Ge4.63

We have investigated magnetic properties of the rare-earth based intermetallic compound Yb3Ni11Ge4.63 (YNG), where Yb3+ ions form a breathing-kagome lattice. Single-site 4 f electron wavefunctions of the ground-state doublet are deduced from magnetization and heat capacity measurements. The Weiss temperatures are quite anisotropic as circle minus(a) = -0.01(2) K (H parallel to a) and circle minus(c) = -0.67(2) K (H parallel to c), indicating Ising-like spin-spin interactions dominating in this compound. Low-temperature neutron diffraction confirms absence of magnetic Bragg peaks down to 0.05 K, whereas enhancement of broad peaks below 0.8K was observed, a signature of short-range spin correlations. Competing interactions on the breathing-kagome lattice would suppress a magnetic long-range order in YNG.