Yoshitomo Karaki

Quantum Criticality Without Tuning in the Mixed Valence Compound β-YbAlB4

A quantum phase transition is observed in a stoichiometric compound at ambient pressure and in zero magnetic field. Fermi liquid theory, the standard theory of metals, has been challenged by a number of observations of anomalous metallic behavior found in the vicinity of a quantum phase transition. The breakdown of the Fermi liquid is accomplished by fine-tuning the material to a quantum critical point by using a control parameter such as the magnetic field, pressure, or chemical composition. Our high-precision magnetization measurements of the ultrapure f-electron–based superconductor β-YbAlB4 demonstrate a scaling of its free energy that is indicative of zero-field quantum criticality without tuning in a metal. The breakdown of Fermi liquid behavior takes place in a mixed-valence state, which is in sharp contrast with other known examples of quantum critical f-electron systems that are magnetic Kondo lattice systems with integral valence.

Magnetic ordering of quasi-1 D Heisenberg antiferromagnet Cu benzoate at sub-mK temperatures

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Specific heat of beryllium-copper alloy at very low temperature

-YbAlB

Ferromagnetic nuclear spin order of scandium

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Field Evolution of Quantum Critical and Heavy Fermi-Liquid Components in the Magnetization of the Mixed Valence Compound β-YbAlB4

is the locally isostructural polymorph of

Spin Glass-like Behaviors in a Frustrated Antiferromagnet MnCl2-GIC

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Ferrimagnetic Phase Transition in Antiferromagnetic Triangular Ising Lattice: NaNi Acac3·benzene

-YbAlB

T/B scaling of magnetization in the mixed valent compound β-YbAlB4

_4

Low-temperature magnetization of the quantum critical heavy fermion superconductor β-YbAlB4

, the first example of an Yb-based heavy fermion superconductor which exhibits pronounced non-Fermi-liquid behavior above