Competition of the longitudinal resonance and the transverse resonance

Observation of the competition of the longitudinal resonance and the transverse resonance is reported.     

Carrier concentration dependence and impurity effects of microwave response in Bi2Sr2CaCu2O8+ y

We report the surface impedance (Z _s ) measurements in high quality single crystals of Bi₂Sr₂CaCu₂O_8+y . At relatively low oxygen content, the change of the penetration depth, Δλ(T) ≡λ(T)-λ(0), of the pure single crystals exhibits linear temperature dependence both parallel to the CuO₂ planes and in thec direction. In contrast to this behavior, by further oxygenation or 0.6% Zn substitution, theT-linear dependence is disrupted andT ² dependence of Δλ is observed. We also found that 0.9% Ni-substitution induces no pairbreaking effect. The present results suggest that the low-lying excitation spectrum of quasiparticles depends on the carrier concentration and is easily changed by a small amount of Zn substitution.     

Population inversion by near-resonant sequential optical pulses

Population inversion by near-resonant sequential optical pulses is proposed. A complete understanding of the population inversion by the near-resonant optical pulses is provided by the vector model.     

Biliary excretion of essential trace elements in rats under oxidative stress caused by selenium deficiency

The excretion of essential trace elements, namely, Se, Sr, As, Mn, Co, V, Fe, and Zn into the bile of Se-deficient (SeD) Wistar male rats was studied using the multitracer (MT) technique, and instrumental neutron activation analysis (INAA). Normal and Se-control (SeC) rat groups were used as reference groups to compare the effects of Se levels on the behaviors of the essential trace elements. The excretion (% dose) of Se, Sr, As, Mn, Co, and V increased with Se levels in the liver. The biliary excretion of Mn and As dramatically enhanced for SeC rats compared with SeD rats, while that of V accelerated a little for SeC rats. The radioactivity levels of ⁵⁹Fe and ⁶⁵Zn in the MT tracer solution were insufficient to measure their excretion into bile. The role of glutathione and bilirubin for biliary excretion of the metals was discussed in relation to Se levels in rat liver.     

Expanding family of π-conjugated trinuclear dithiolenes: the cases of group 8 (Ru(II)) and 10 (Ni(II) and Pt(II)) metals

New π-conjugated trinuclear dithiolenes with group 8 (6, Ru(II)) and 10 (7 and 8, Ni(II) and Pt(II)) metals were synthesized. Compounds 6 and 7 exhibited intense electronic communication through the phenylene bridge among the three dithiolene moieties during oxidation of the metalladithiolene rings, which has not been confirmed in the analogous family of group 9 metals, 1-5. Compound 8 exhibited an intense absorption band across the visible and near-IR regions, which was assigned as a charge transfer to the diimine and was red-shifted and broadened compared to the corresponding band of the mononuclear complex.     

Multinuclear metalladithiolenes: focusing on electronic communication in mixed-valent states

This Perspective addresses our recent studies relating to metalladithiolenes and their cluster complexes that exhibit peculiar electronic communication in mixed-valent (MV) states. Chapter 1 provides an introduction for the Perspective. Chapter 2 enumerates a series of phenylene-annulated π-conjugated trinuclear metalladithiolenes with intense electronic communication in the MV states. Chapter 3 treats heterometal cluster complexes synthesized by integrating zero-valent metal carbonyls on mononuclear metalladithiolenes, taking advantage of the coordination unsaturation of the latter. In the field of MV chemistry, their electronic communication through metal-metal bonds and potential inversion behavior are intriguing properties. Chapter 4 describes hexanuclear and nonanuclear heterometal cluster complexes created in combination with the methods introduced in Chapters 2 and 3. The resultant heterometal cluster complexes feature electronic communication through the vast phenylene-annulated π-conjugated trinuclear metalladithiolene frameworks, the intensity of which correlates with their planarity. Each chapter describes the synthesis, structural features, and electrochemical properties of the relevant compounds.     

Generic phase diagram of “electron-doped” T′ cuprates

We investigated the generic phase diagram of the electron doped superconductor, Nd_2−xCe_xCuO₄, using films prepared by metal organic decomposition. After careful oxygen reduction treatment to remove interstitial O_ap atoms, we found that the T_c increases monotonically from 24 K to 29 K with decreasing x from 0.15 to 0.00, demonstrating a quite different phase diagram from the previous bulk one. The implication of our results is discussed on the basis of tremendous influence of O_ap “impurities” on superconductivity and also magnetism in T′ cuprates. Then we conclude that our result represents the generic phase diagram for oxygen-stoichiometric Nd_2−xCe_xCuO₄.