Sr 4 Ru 3 O 10 is characterized by a sharp metamagnetic transition and ferromagnetic behavior occurring within the basal plane and along the c-axis, respectively. Resistivity at magnetic field, B, exhibits low-frequency quantum oscillations when B||c-axis and large magnetoresistivity accompanied by critical fluctuations driven by the metamagnetism when B⊥c-axis. The complex behavior evidenced in resistivity, magnetization and specific heat presented is not characteristic of any obvious ground states, and points to an exotic state that shows a delicate balance between fluctuations and order.

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We have synthesized and studied single-crystal Ba 5 AlIr 2 O 11 that features dimer chains of two inequivalent octahedra occupied by tetravalent Ir 4+ (5d 5 ) and pentavalent Ir 5+ (5d 4 ) ions, respectively. Ba 5 AlIr 2 O 11 is a Mott insulator that undergoes a subtle structural phase transition near T S = 210 K and a magnetic transition at T M = 4.5 K; the latter transition is surprisingly resistant to applied magnetic fields μ o H ≤ 12 T, but more sensitive to modest applied pressure (dT M /dp ≈ +0.61 K/GPa). All results indicate that the phase transition at T S signals an enhanced charge order that induces electrical dipoles and strong dielectric response near T S . It is clear that the strong covalency and spin-orbit interaction (SOI) suppress double exchange in Ir dimers and stabilize a novel magnetic state that is neither S = 3/2 nor J = ½, but rather lies in an "intermediate" regime between these two states. The novel behavior of Ba 5 AlIr 2 O 11 therefore provides unique insights 2 into the physics of SOI along with strong covalency in competition with double exchange interactions of comparable strength. : 71.27.+a, 71.70.Ej, Introduction The 5d-electron based iridates are distinguished by strong spin-orbit PACS

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Persulfate-based advanced oxidation has been widely applied in environmental remediation for degrading contaminants. In recent years, numerous kinds of organic analytes including pesticides, dyes and pharmaceuticals, have emerged and related researches on the activation methods, the mechanism and the application have been performed. The activation is critical in persulfate-based advanced oxidation because the persulfate alone has a weaker oxidation potential to degrade these organic pollutants. Hence various activation methods have been extensively investigated to achieve a higher oxidation efficiency. These novel methods are gradually expanding the applicability and practicality. This review focuses on the classification of the different activation methods based on whether it is related to the substances or not. The effect of the environmental conditions (solution pH, dosage and the co-existing substance) on the oxidation capacity are also discussed.

A crossover from negative to positive magnetoresistance (MR) is observed in the heterojunction composed of a La0.7Ce0.3MnO3 film and a 0.5wt.% Nb-doped SrTiO3 substrate. The temperature and bias current dependences of MR sign in the junction are investigated carefully. It is found that the positive MR occurs when temperature or applied bias current is increased to a higher value. The relation between MR and an external magnetic field is also found to be temperature dependent. We attribute the appearance of the positive MR at higher temperatures to the tunneling transport mechanism. These results are helpful in configuring artificial devices using manganite-based heterojunctions.

-dependence of the resisitivity. The drastic changes caused by the dilute doping demonstrate a rare borderline magnetism that is delicately linked to the interplay of the density of states and spin-orbit coupling.

Sr n+1 Ru n O 3n+1 represents a class of layered materials whose physical properties are a strong function of the number of Ru-O layers per unit cell, n. This series includes the p-wave superconductor Sr 2 RuO 4 (n=1), enhanced paramagnetic Sr 3 Ru 2 O 7 (n=2), nearly ferromagnetic Sr 4 Ru 3 O 10 (n=3) and itinerant ferromagnetic SrRuO 3 (n=∞). In spite of a wide spectrum of physical phenomena, this series of materials along with paramagnetic CaRuO 3 shares two major characteristics, namely, robust Fermi liquid behavior at low temperatures and anomalous transport behavior featured by linear temperature dependence of resistivity at high temperature where electron wavepackets are no longer clearly defined. There is no crossover separating such two fundamentally different states. In this paper, we report results of our study that systematically addresses anisotropy and temperature dependence of basal-plane and c-axis resistivity as a function of n for the entire Sr n+1 Ru n O 3n+1 series and CaRuO 3 and for a wide temperature range of 1.7 K