Annealing behavior of neon-implanted magnetic garnet

Ferromagnetic resonance spectra and x-ray rocking curves were used to measure the change in magnetic properties and strain with annealing temperature in the surface layer of (111)-oriented Gd, Tm, Ga substituted yttrium iron garnet films implanted with Ne+ at 190 keV. For doses below about 4×10^14 ions/cm^2, the entire implanted layer remains crystalline and magnetic. The implantation-induced strain decreases monotonically with increasing annealing temperature, falling to zero at a temperature of 1100 °C. The implantation-induced magnetic anisotropy varies with strain in the same manner as for unannealed material until the annealing temperature reaches 800 °C. For higher temperatures, the anisotropy has a value larger than that expected for unannealed material. At a higher dose, 5×10^14 ions/cm^2, the center of the implanted region is both amorphous and nonferrimagnetic. Single-crystal order and ferrimagnetism return with annealing near 500 °C. The magnetization and exchange constant decrease with increasing dose, and annealing at 1100 °C restores them to bulk values

Annealing behavior of hydrogen-implanted magnetic garnet

Ferromagnetic resonance spectra and x-ray rocking curves were used to measure magnetic and strain profiles of Gd, Tm, Ga substituted yttrium iron garnet films implanted with H2 + at 120 keV and at doses in the range (3–80)×10^15 ions/cm^2. The maximum strain occurred at a depth of 3600 Å, reaching a value of 2.9% at 40×10^15 ions/cm^2. At the highest dose, the garnet was amorphous in that region which had highest strain at lower dose. The strain has two components, one due to damage and one due to the presence of the hydrogen atoms. The second component disappears for annealing temperatures above 400 °C, at which temperature the hydrogen has been reported to be largely desorbed. The reduction of the first component with annealing follows the same pattern as other implant elements. The magnetic anisotropy exhibits a large anomalous nonlinear increase with dose. The excess over other implantation elements disappears for annealing temperatures above 400 °C. There is no significant change in gyromagnetic ratio with dose or annealing temperatures up to 600 °C

Broadband Spectroscopy of Nanoporous-Gold Promoter

The efficiency of UV photocatalysis on TiO2 particles was increased by mixing TiO2 particles with nanoporous gold (NPG) with pore diameters of 10–40 nm. This means that NPG acts as a promoter in the photocatalytic reaction of TiO2. Broadband spectroscopic results from millimeter wave to ultra violet of NPG membrane are discussed to estimate plasmonic effect on the catalysis

Stable ultrahigh-density magneto-optical recordings using introduced linear defects

The stability of data bits in magnetic recording media at ultrahigh densities is compromised by thermal `flips' -- magnetic spin reversals -- of nano-sized spin domains, which erase the stored information. Media that are magnetized perpendicular to the plane of the film, such as ultrathin cobalt films or multilayered structures, are more stable against thermal self-erasure than conventional memory devices. In this context, magneto-optical memories seem particularly promising for ultrahigh-density recording on portable disks, and bit densities of $\sim$100 Gbit inch$^{-2}$ have been demonstrated using recent advances in the bit writing and reading techniques. But the roughness and mobility of the magnetic domain walls prevents closer packing of the magnetic bits, and therefore presents a challenge to reaching even higher bit densities. Here we report that the strain imposed by a linear defect in a magnetic thin film can smooth rough domain walls over regions hundreds of micrometers in size, and halt their motion. A scaling analysis of this process, based on the generic physics of disorder-controlled elastic lines, points to a simple way by which magnetic media might be prepared that can store data at densities in excess of 1 Tbit inch$^{-2}$.Comment: 5 pages, 4 figures, see also an article in TRN News at http://www.trnmag.com/Stories/041801/Defects_boost_disc_capacity_041801.htm

Correlation between laser accelerated MeV proton and electron beams using simple fluid model for target normal sheath acceleration

Copyright 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 17(7), 073110, 2010 and may be found at http://dx.doi.org/10.1063/1.345906

The chaperone protein clusterin may serve as a cerebrospinal fluid biomarker for chronic spinal cord disorders in the dog

Chronic spinal cord dysfunction occurs in dogs as a consequence of diverse aetiologies, including long-standing spinal cord compression and insidious neurodegenerative conditions. One such neurodegenerative condition is canine degenerative myelopathy (DM), which clinically is a challenge to differentiate from other chronic spinal cord conditions. Although the clinical diagnosis of DM can be strengthened by the identification of the Sod1 mutations that are observed in affected dogs, genetic analysis alone is insufficient to provide a definitive diagnosis. There is a requirement to identify biomarkers that can differentiate conditions with a similar clinical presentation, thus facilitating patient diagnostic and management strategies. A comparison of the cerebrospinal fluid (CSF) protein gel electrophoresis profile between idiopathic epilepsy (IE) and DM identified a protein band that was more prominent in DM. This band was subsequently found to contain a multifunctional protein clusterin (apolipoprotein J) that is protective against endoplasmic reticulum (ER) stress-mediated apoptosis, oxidative stress, and also serves as an extracellular chaperone influencing protein aggregation. Western blot analysis of CSF clusterin confirmed elevated levels in DM compared to IE (p < 0.05). Analysis of spinal cord tissue from DM and control material found that clusterin expression was evident in neurons and that the clusterin mRNA levels from tissue extracts were elevated in DM compared to the control. The plasma clusterin levels was comparable between these groups. However, a comparison of clusterin CSF levels in a number of neurological conditions found that clusterin was elevated in both DM and chronic intervertebral disc disease (cIVDD) but not in meningoencephalitis and IE. These findings indicate that clusterin may potentially serve as a marker for chronic spinal cord disease in the dog; however, additional markers are required to differentiate DM from a concurrent condition such as cIVDD