A peak field of 1200 T was generated by the electromagnetic flux-compression (EMFC) technique with a newly developed megagauss generator system. Magnetic fields closely up to the turn-around peak were recorded by a reflection-type Faraday rotation magnetic-field optical-fiber probe. The performance was analyzed and compared with data obtained by the preceding EMFC experiments to show a significant increase in the liner imploding speed of up to 5 km/s.

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Geometrical frustration and a high magnetic field are two key factors for realizing unconventional quantum states in magnetic materials. Specifically, conventional magnetic order can potentially be destroyed by competing interactions and may be replaced by an exotic state that is characterized in terms of quasiparticles called magnons, the density and chemical potential of which are controlled by the magnetic field. Here we show that a synthetic copper mineral, Cd-kapellasite, which comprises a kagomé lattice consisting of corner-sharing triangles of spin-1/2 Cu2+ ions, exhibits an unprecedented series of fractional magnetization plateaus in ultrahigh magnetic fields of up to 160 T. We propose that these quantum states can be interpreted as crystallizations of emergent magnons localized on the hexagon of the kagomé lattice.

The authors recently succeeded in growing two-dimensional ZnO nanowalls on sapphire substrates using high-pressure pulsed laser deposition (PLD) without any catalysts. Depending on the PLD growth conditions and the composition of the target, ZnO nanowalls with thickness of tens of nanometers and dimension of several micrometers were synthesized reproducibly. Most of the nanowalls were vertically epitaxial on the c-cut sapphire substrates with a preferred c-axis orientation as confirmed with X-ray diffraction and transmission electron microscopy. The room temperature photoluminescence spectrum of such a ZnO nanowall exhibited a strong intrinsic UV emission and a week defect-related visible emission. It was found that the ZnO nanowalls showed stable field emission properties with low threshold field and a big field enhancement factor. Photocurrent measurements also indicated that these ZnO nanowall films showed a high sensitivity to UV light, which can be used as a UV photodetector.

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We characterize extreme ultraviolet (EUV) emission from mid-infrared (mid-IR) laser-produced plasmas (LPPs) of the rare-earth element Gd. The energy conversion efficiency (CE) and the spectral purity in the mid-IR LPPs at λL = 10.6 μm were higher than for solid-state LPPs at λL = 1.06 μm, because the plasma produced is optically thin due to the lower critical density, resulting in a CE of 0.7%. The peak wavelength remained fixed at 6.76 nm for all laser intensities studied. Plasma parameters at a mid-IR laser intensity of 1.3×10(11) W/cm(2) was also evaluated by use of the hydrodynamic simulation code to produce the EUV emission at 6.76 nm.

JapanFrequency-dependent terahertz conductivities of La 2−x Sr x CuO 4 thin films with various carrier concentrations were investigated. The imaginary part of the complex conductivity considerably increased from far above a zero-resistance superconducting transition temperature, T zero c , because of the existence of the fluctuating superfluid density with a short lifetime. The onset temperature of the superconducting fluctuation is at most ∼ 2T zero c for underdoped samples, which is consistent with the previously reported analysis of microwave conductivity. The superconducting fluctuation was not enhanced under a 0.5 T magnetic field. We also found that the temperature dependence of the superconducting fluctuation was sensitive to the carrier concentration of La 2−x Sr x CuO 4 , which reflects the difference in the nature of the critical dynamics near the superconducting transition temperature. Our results suggest that the onset temperature of the Nernst signal is not related to the superconducting fluctuation we argued in this paper.

Metal-insulator (MI) transitions in correlated electron systems have long been a central and controversial issue in material science. Vanadium dioxide (VO 2) exhibits a first-order MI transition at 340 K. For more than half a century, it has been debated whether electron correlation or the structural instability due to dimerised V ions is the more essential driving force behind this MI transition. Here, we show that an ultrahigh magnetic field of 500 T renders the insulator phase of tungsten (W)-doped VO 2 metallic. The spin Zeeman effect on the d electrons of the V ions dissociates the dimers in the insulating phase, resulting in the delocalisation of electrons. As the Mott-Hubbard gap essentially does not depend on the spin degree of freedom, the structural instability is likely to be the more essential driving force behind the MI transition.