A wide bandwidth continuous-time sigma-delta ADC, operating between 20 and 40 MS/s output data rate, is implemented in 130-nm CMOS. The circuit is targeted for applications that demand high bandwidth, high resolution, and low power, such as wireless and wireline communications, medical imaging, video, and instrumentation. The third-order continuous-time 61 modulator comprises a third-order RC operational-amplifier-based loop filter and 4-bit internal quantizer operating at 640 MHz. A 400-fs rms jitter LC PLL with 450-kHz bandwidth is integrated, generating the low-jitter clock for the jitter-sensitive continuous-time 61 ADC from a single-ended input clock between 13.5 and 40 MHz. To reduce clock jitter sensitivity, nonreturn-to-zero (NRZ) DAC pulse shaping is used. The excess loop delay is set to half the sampling period of the quantizer and the degradation of modulator stability due to excess loop delay is avoided with a new architecture. The 61 ADC achieves 76-dB SNR, 78-dB THD, and a 74-dB SNDR or 12 ENOB over a 20-MHz signal band at an OSR of 16. The power consumption of the CT 61 modulator itself is 20 mW and in total the ADC dissipates 58 mW from the 1.2-V supply.

Ferromagnetic nanomaterials exhibit unique magnetic properties common to materials with dimensions approaching the atomic scale and have potential applications in magnetic data storage. Technological applications, however, require that the detailed magnetic behaviors and configurations of individual and interacting magnetic nano-objects be clarified. We determined the magnetic remnant configurations in single crystalline 30 nm Fe nanocubes and groups of nanocubes using off-axis electron holography in a transmission electron microscope. Our measurements on an isolated cube reveal a vortex state whose core size has been determined. Two neighboring nanocubes with adjacent {100} surfaces exhibit a ferromagnetic dipolar coupling, while similar magnetic interactions between four cubes in a square arrangement induce a bending of the magnetic induction, i.e., a magnetic flux closure state. The various configurations were successfully simulated by micromagnetic calculations.

Stable iron nanoparticles have been synthesised by the decomposition of {Fe(N[Si(CH(3))(3)](2))(2)}(2) under dihydrogen pressure. Those conditions lead to a system of monodisperse and metallic nanoparticles which diameter is less than 2 nm and stabilized by HN[Si(CH(3))(3)](2). The magnetization is found to be M(S)=1.92 mu(B)/at., i.e., 10% lower than the bulk value. The Mossbauer spectrum is fitted by two contributions of metallic iron. The magnetic anisotropy energy constant increases up to 5.2x10(5) J/m(3), i.e., ten times the bulk one

The different spin configurations in the vicinity of the single-domain/vortex transition are reported in isolated magnetic nanoparticles. By combining chemical synthesis, electron holography in a dedicated transmission electron microscope and micromagnetic simulations, we establish the "magnetic configurations vs size" phase diagram of Fe single-crystalline nanocubes. Room temperature high resolution magnetic maps reveal the transition between single-domain and vortex states for Fe nanocubes from 25 to 27 nm, respectively. An intermediate spin configuration consisting of an ⟨111⟩ vortex is for the first time evidenced.