To elucidate the ground state of the pressure-stabilized high-temperature ͑HT͒ phase of YbInCu 4 , we have carried out electrical resistivity and ac-susceptibility ac measurements at high pressures. For pressures above 2.49 GPa, the first-order valence transition is completely suppressed ͑below ϳ80 mK). Separately, above 2.39 GPa, a clear peak appears in ac with a small kink in at around T M ϭ2.4 K. The ac peak is easily diminished by applying low magnetic fields and disappears above ϳ500 Oe. The characteristic behavior of ac at T M can generally be ascribed to the onset of long-range ferromagnetic ordering and, therefore, the ground state of the pressure-stabilized HT phase is most probably a ferromagnetically ordered state. This result is compatible with the occurrence of weak ferromagnetism recently reported for the Y-substituted compound Yb 0.8 Y 0.2 InCu 4 under pressure of 1.2 GPa.

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The quantum criticality of the Yb-based heavy fermion compound YbAuCu 4 with noninteger valence close to unity has been investigated through low-temperature resistivity, magnetization, and nuclear magnetic resonance measurements in several fixed magnetic fields H . We found that, with increasing H , YbAuCu 4 is driven from the originally antiferromagnetically ordered ground state (Néel temperature T N ∼ 0.9 K) to a nonmagnetic Fermi liquid one through the field-tuned quantum critical point (QCP) at H cr 13 kOe. The experimental results also provide the first evidence that a crossover valence transition near the magnetic QCP is stabilized with the application of external field, in marked contrast to the destabilization of the first-order valence transition. The T -H phase diagram of YbAuCu 4 and the T -X phase diagram established for the YbXCu 4 (X = Pd, Au, Cu, Ag) series indicate that the evolution of valence fluctuations near the magnetic QCP quickly interacts with the critical spin fluctuations. We suggest that the competition between the Kondo temperature and crossover valence transition temperature is central to the long-standing puzzles of localized-itinerant duality and the extent of degeneracy in the crystal electric field ground state.

This paper introduces a new approach to measure the muon magnetic moment anomaly a µ = (g − 2)/2, and the muon electric dipole moment (EDM) d µ at the J-PARC muon facility. The goal of our experiment is to measure a µ and d µ using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon g − 2 experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1,000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for a µ is statistical uncertainty of 450 part per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of 1.5 × 10 −21 e • cm.

Metal halide perovskites are promising for direct X-ray detection applications thanks to their high X-ray absorption capability and excellent charge carrier transport. Single-pixelated perovskite Xray detectors have hitherto demonstrated excellent device performance, including high sensitivity and detectivity. On the other hand, multipixel flat-panel detectors (FPDs) that enable 2D X-ray imaging are undeveloped due to challenges in scalable deposition processes. In this perspective, we summarize promising scalable perovskite deposition processes and discuss the challenges and opportunities toward direct X-ray FPD applications.