Playback performance of perpendicular magnetic recording tape media for over-50-TB cartridge by facing targets sputtering method

Perpendicular magnetic recording tape medium with laminated soft magnetic underlayers was successively formed on a 4.5 μm thin plastic film by the facing targets sputtering method at room temperature. The tape medium showed extremely high SNR values with sharp transitions in playback tests by a drum tester, compared to a linear format commercial tape medium. An areal density of 45.0 Gb/in.² of perpendicular tape medium was confirmed by a high-resolution contact tester. These results suggest that the perpendicular recording tape medium by the facing targets sputtering method is a promising candidate for a tape cartridge of over 50-TB.     

Ecological interaction and phylogeny, studying functionality on composed networks

We study a class of composed networks that are formed by two tree networks, T_P and T_A, whose end points touch each other through a bipartite network B_PA. We explore this network using a functional approach. We are interested in how much the topology, or the structure, of T_X (X=A or P) determines the links of B_PA. This composed structure is a useful model in evolutionary biology, where T_P and T_A are the phylogenetic trees of plants and animals that interact in an ecological community. We make use of ecological networks of dispersion of fruits, which are formed by frugivorous animals and plants with fruits; the animals, usually birds, eat fruits and disperse their seeds. We analyse how the phylogeny of T_X determines or is correlated with B_PA using a Monte Carlo approach. We use the phylogenetic distance among elements that interact with a given species to construct an index κ that quantifies the influence of T_X over B_PA. The algorithm is based on the assumption that interaction matrices that follows a phylogeny of T_X have a total phylogenetic distance smaller than the average distance of an ensemble of Monte Carlo realisations. We find that the effect of phylogeny of animal species is more pronounced in the ecological matrix than plant phylogeny.     

Magnetic properties of Mn-rich Rh2Mn1+xSn1−x Heusler alloys

X-ray powder diffraction and magnetization measurements have been carried out on Rh₂Mn_1+xSn_1−x (0≤x≤0.3) alloys. The alloys, which crystallize in the L2₁ structure, were found to exhibit ferromagnetic behavior. The lattice constant a at room temperature decreases with increasing x, whereas the Curie temperature T_C decreases linearly. At 5 K the magnetic moment per formula unit first increases with increasing x and then saturates for x≥0.2. The experimental results are discussed in terms of the influence of the Mn-Mn exchange interactions between the Mn atoms on the Sn and Mn sites.     

Magnetic Relaxometry with an Atomic Magnetometer and SQUID Sensors on Targeted Cancer Cells

Magnetic relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting Quantum Interference Device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 magnetically-labeled cancer cells. The emerging technology of atomic magnetometers (AM) represents a new detection method for magnetic relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of magnetic relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the magnetic decay characteristics following a magnetization pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and magnetic moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting magnetically labeled cells does not require cryogenic cooling and is relatively inexpensive.     

Fragmentation trees for the structural characterisation of metabolites

Metabolite identification plays a crucial role in the interpretation of metabolomics research results. Due to its sensitivity and widespread implementation, a favourite analytical method used in metabolomics is electrospray mass spectrometry. In this paper, we demonstrate our results in attempting to incorporate the potentials of multistage mass spectrometry into the metabolite identification routine. New software tools were developed and implemented which facilitate the analysis of multistage mass spectra and allow for efficient removal of spectral artefacts. The pre-processed fragmentation patterns are saved as fragmentation trees. Fragmentation trees are characteristic of molecular structure. We demonstrate the reproducibility and robustness of the acquisition of such trees on a model compound. The specificity of fragmentation trees allows for distinguishing structural isomers, as shown on a pair of isomeric prostaglandins. This approach to the analysis of the multistage mass spectral characterisation of compounds is an important step towards formulating a generic metabolite identification method. Copyright ? 2012 John Wiley & Sons, Ltd.     

Low-temperature magnetoresistance due to weak localization in lightly doped semiconductors

The first observation of low-temperature magnetoresistance (MR) of interference nature in the case of a light doping is reported. The MR occurs in n- and p-type Ge samples at a frequency of 10 GHz at temperatures below 30 K in weak magnetic fields on the background of the classical MR effect associated with electrons in different valleys (n-Ge) and with heavy and light holes (p-Ge).     

How to obtain magnetocapacitance effects at room temperature: The case of Mn-doped BiFeO3

The magnetoelectric properties of a rhombohedrally distorted perovskite BiFe_0.7Mn_0.3O₃ are reported. An anomaly in the dielectric constant, related to enhanced thermal fluctuations around the antiferromagnetic transition, was induced near room temperature by the substitution of Mn for Fe in BiFeO₃. This substitution also brings about non-trivial magnetocapacitance effects at room temperature.     

Limit on the electron electric dipole moment in gadolinium-iron garnet

A new method for the detection of the electron electric dipole moment (EDM) using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the sample's magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron EDM of 5 x 10(-24)e cm, which is a factor of 40 below the limit obtained from the only previous solid-state EDM experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization.     

Search for [corrected] B0(s) --> mu+ mu- and B0(d) [corrected] --> mu + mu- decays in pp collisions with CDF II

We report on a search for B0(s) --> mu+ mu- and B0(d) --> mu + mu- decays in pp collisions at square root(s) = 1.96 TeV using 364 pb(-1) of data collected by the CDF II detector at the Fermilab Tevatron Collider. After applying all selection requirements, we observe no candidates inside the B0(s) or B0(d) mass windows. The resulting upper limits on the branching fractions are B(B0(s) --> mu+ mu-) < 1.5 x 10(-7) and B(B0(d) --> mu+ mu-) < 3.9 x 10(-8) at 90% confidence level.