Low-frequency magnetic noise in micron-scale magnetic tunnel junctions

We have observed low-frequency noise due to quasiequilibrium thermal magnetization fluctuations in micron-scale magnetic tunnel junctions (MTJs). This strongly field-dependent magnetic noise occurs within the magnetic hysteresis loops, either as 1/f or Lorentzian (random telegraph) noise. We attribute it to the thermally excited hopping of magnetic domain walls between pinning sites. Our results show that magnetic stability is a crucial factor in reducing the low-frequency noise in small MTJs.     

Observation of inner electron ionization from radial rydberg wave packets in two-electron atoms

We have observed multiphoton ionization of the 5s core electron from a 5snd radial Rydberg wave packet of Sr atoms using a short optical pulse. When the outer nd electron is at its outer turning point the inner 5s electron is removed from the atom, and the outer electron is left in a Sr+ Rydberg state, but when the outer electron is at the inner turning point this does not occur. Analysis of the final Sr+ Rydberg states shows that the two electrons interact as the inner electron leaves, so that the outer electron is not simply projected onto the Sr+ Rydberg states.     

A novel approach for the computation of orthonormal polynomial expansions

In this paper we present a novel technique for the computation of orthonormal polynomial expansions. The proposed method is very straightforward; given a function to be expanded in a polynomial series, we first use the FFT to compute a vector of Fourier coefficients. Then, using a change of basis transformation, we go from the Fourier coefficients to the polynomial coefficients. Convergence properties for this new approach are investigated.     

Aflavinine,a novel indole-mevalonate metabolite from tremorgen-producing aspergillusflavus species

The structure of aflavanine, a new diterpene indole from $\text{A}$. $\text{flavus}$, is presented.     

(μ-dithio)bis(tricarbonyliron) as an organic disulfide mimic: insertion of low-valent metal species into the sulfursulfur bond

Low valent metal species: (Ph₂PCH₂CH₂PPh₂)Ni⁰, (Ph₃P)₂Pd⁰, (Ph₃P)₂Pt⁰, η⁵-C₅H₅ Co^I and (CH₃)₂Sn^II insert into the SS bond of (μ-S₂)Fe₂(CO)₆ under mild conditions. Identical products were obtained by reactions of the dianion, [(μ-S₂)Fe₂(CO)₆]^2? with the corresponding metal chlorides.     

Spin density of states of proximity effect superconducting sandwiches in high fields

We use a tunneling Hamiltonian model to study the behavior of a thin film superconducting-normal metal sandwich in a parallel magnetic field including the effects of Pauli spin paramagnetism. The field acts to spin-split the density of states of the superconductor and the normal metal. With increasing magnetic field the sandwich displays zero temperature electron spin paramagnetism and a first-order transition to the normal state. We present a calculation of the field dependence of the density of states and order parameter.     

Na 32P-32D line broadening by Ne,Ar, and Xe

The normalized emission intensity in the wings of the optically thin Na 3²P-3²D lines broadened by Ne, Ar, and Xe has been measured in emission from a high-pressure discharge. A blended satellite occurs about 80 cm^-1 into the Na-Xe red wing and a progression of increasing red wing intensity from Ne to Ar to Xe is observed. Xe densities of 2.5 and 9.1 × 10¹⁹ cm^-3 were used, and the pressure dependence of the NaXe line shape indicates that multiple perturber interactions are important in the far wing at the higher noble gas densities.     

The mass spectra of 5,10-dihydro-5-10-o-benzenophenarsazine (azarsatriptycene) and its oxide

The fragmentation of azarsatriptycene and its oxide proceed with initial rearrangement of the molecular ion to give polycyclic systems: it is suggested that similar rearrangements may account for the behaviour of triptycene itself in the mass spectrometer.