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Megaelectronvolt (MeV) ion beams with low divergence (10°) are experimentally generated from a thin foil irradiated by an ultrahigh-contrast laser at a peak intensity of ∼1018 W/cm2. The high-contrast (∼1011) laser is obtained with a pulse cleaner based on noncollinear optical-parametric amplification and second-harmonic generation processes. The effects of the foil density, foil thickness, as well as the density gradients at the front and back sides of the foil are investigated with two-dimensional particle-in-cell simulations. The beam parameters of maximum energy and divergence strongly depend on the density gradients at the back side of the foil. [ABSTRACT FROM AUTHOR]

The erasing characteristics of Cu2O metal-insulator-metal resistive switching memory were measured on a 64 Kb memory test array. The erasing yield reaches the maximum at an optimal erasing voltage. Effective erasing requires a threshold current compliance that is higher for shorter pulse width. The erasing current and erasing power both depend strongly on the on-state before erasing, while the erasing voltage is essentially unaffected. Erasing appears to be a power-driven process, which may be related to the thermal effect of power dissipation. The experimental data and analysis suggest that erasing can be explained by field-assisted thermal emission of trapped charges. [ABSTRACT FROM AUTHOR]

The Cu2O metal-insulator-metal (MIM) resistive switching memory was characterized on a 64 kb memory test array. The switching properties are consistent with the proposed switching model of conductivity modulation by a charge trapping process. Retention, programing characteristics, and temperature effects are analyzed based on the switching model. The measured characteristics and the switching model for Cu2O MIM are compared with those of other resistive switching materials. The statistical characteristics provide essential evidence for analysis of the switching mechanism and evaluation of the memory devices. [ABSTRACT FROM AUTHOR]

The ordering temperature of FePt films grown on PtMn underlayers was reduced due to phase transformation of the PtMn L10 phase. The in-plane coercivity of 10 nm FePt on 50 nm PtMn underlayers was 7688 Oe after annealing at 325 °C. An exchange field of 554 Oe was also observed, which indicates that PtMn may not only induce the ordering of FePt at a reduced temperature, but also may provide extra anisotropy. A large coercivity of 10500 Oe can be achieved for 35 nm FePt films on PtMn underlayers after 325 °C annealing. [ABSTRACT FROM AUTHOR]