We report the electrical detection of magnetization dynamics in an Al/AlOx/Ni80Fe20/Cu tunnel junction, where a Ni80Fe20 ferromagnetic layer is brought into precession under ferromagnetic resonance conditions. The dc voltage generated across the junction by the precessing ferromagnet is enhanced about an order of magnitude compared to the voltage signal observed when the contacts in this type of multilayered structure are Ohmic. We discuss the relation of this phenomenon to magnetic spin pumping and speculate on other possible underlying mechanisms responsible for the enhanced electrical signal.

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In recent years, terahertz (THz) sources between 0.1 THz and 10 THz have attracted much attention for imaging and sensing applications. THz emission from radiative transitions in impurity states has been demonstrated in Si and Ge devices by either electrical or optical pumping. Compared to Si as the material for THz emission, the wide-band-gap material SiC exhibits several advantages such as a higher dopant ionization energy, which allows a higher device operating temperature. Combining with its superior material qualities such as high breakdown field and high thermal conductivity, SiC is a promising material for high-temperature and high-power THz emitting devices. This article describes recent progress in using SiC materials to increase the operating temperature and output power of dopant-based THz sources.

High power electroluminescence near 8THz was observed from boron doped silicon devices operating at heat sink temperatures up to 118K. This represents the highest emission temperature yet observed for silicon dopant-based terahertz devices, and is a significant increase from previous reports. This letter compares the temperature dependence of the emission mechanism to the dopant occupation function and describes an empirical model that fits the variation of output power with temperature, and that can guide the design of future terahertz devices.

Current-voltage characterization was used to investigate the behavior of silicon field-effect devices with DNA solutions of various concentrations and molecular states deposited on the gate oxide. These devices were similar to conventional transistors but without gate metal, and no surface treatments or agents were used to immobilize the DNA. With increasing micromolar concentration, significant changes were produced in the device response. The current decreased with increasing ratios of double-to-single stranded populations produced by mixing complementary sequences, and by thermal denaturing. The device characteristics were reproducible. Modeling suggested a mechanism of modifications to the device carrier density induced by variations in the electrochemical properties of the DNA located within a charge screening length of the gate oxide surface. These results showed that field-effect devices may be useful for the real time monitoring of nucleic acids, without binding agents or label tags.