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To understand the plasma evolution mechanism of microwave ion source (MIS), a hybrid discharge heating (HDH) mode is proposed. That mode contains two parts: ignition discharge by surface wave plasma (SWP) and ionization by electron cyclotron resonance. Compared with the traditional electron cyclotron heating (ECH) mode, the HDH mode has a wider scope of application for MIS with a chamber diameter smaller than the cutoff size. The spatio-temporal evolution of electric field, power deposition, electron temperature, and electron density of a miniaturized microwave ion source (MMIS) at Peking University is investigated based on the HDH mode. In addition, the MMIS is optimized based on the theoretical results of the HDH mechanism. Preliminary experiments show that a mixed hydrogen continuous wave beam of up to 25 mA at 30 keV can be extracted with a power efficiency of 25 mA/100 W. [ABSTRACT FROM AUTHOR]

The 4d and 5d transition metal oxides have exhibited a wide spectrum of attracting phenomena. Here, we demonstrate modulations on crystal structure, electrical properties, and spin-orbit couplings (SOCs) in perovskite CaIr1−xRuxO3 (CIRO, 0 ≤ x ≤ 1) thin films. First, all our coherently-grown CIRO films exhibit the orthorhombic perovskite structure, of which the orthorhombicity is tuned by the doping level x. This is different from the post-perovskite structure that is usually observed in the bulk CaIrO3. Second, the metal-semiconductor transition in the perovskite CIRO layers is triggered by changing either the doping level or the layer thickness. Our data suggest the important roles of SOC and disorders in determining the electrical properties in perovskite CIRO layers. Third, the sign reversal of Hall coefficient in CIRO films reveals the complex evolution of electronic structure depending on x and temperature, suggesting the perovskite CIRO films as a new accessible platform for investigating rich physics in 4d and 5d transition metal oxides. [ABSTRACT FROM AUTHOR]