The magnetic ground state of polycrystalline N\'eel skyrmion hosting material
GaV$_4$S$_8$ has been investigated using ac susceptibility and powder neutron
diffraction. In the absence of an applied ...magnetic field GaV$_4$S$_8$ undergoes
a transition from a paramagnetic to a cycloidal state below 13~K and then to a
ferromagnetic-like state below 6~K. With evidence from ac susceptibility and
powder neutron diffraction, we have identified the commensurate magnetic
structure at 1.5 K, with ordered magnetic moments of $0.23(2)~\mu_{\mathrm{B}}$
on the V1 sites and $0.22(1)~\mu_{\mathrm{B}}$ on the V2 sites. These moments
have ferromagnetic-like alignment but with a 39(8)$^{\circ}$ canting of the
magnetic moments on the V2 sites away from the V$_4$ cluster. In the
incommensurate magnetic phase that exists between 6 and 13 K, we provide a
thorough and careful analysis of the cycloidal magnetic structure exhibited by
this material using powder neutron diffraction.
The polarization properties of GaN nanowire lasers are studied experimentally by analyzing their end-facet emission. We demonstrate that the polarization state varies for different transverse modes. ...Linear and elliptical polarizations are observed in our measurements.
The form of the dynamic relaxation of high quality BSCCO 2212 single crystals irradiated with 2.25 GeV Au ions to produce columnar defects along the crystallographic c-axis, is reported. It is found ...that below 10K, the columns do not significantly inhibit flux motion once the vortex density exceeds the column density. Above 10K, and at low vortex densities, the columns depress the dynamic behaviour in a systematic way as a function of temperature. At high vortex densities, the columns are decreasingly effective as the temperature is raised and in a manner which is a non linear function of irradiation dose.
Topological insulators (TIs) and topological crystalline insulators (TCIs) exhibit exotic surface properties. We present optimized growth procedures to obtain high quality bulk crystals of the TCIs ...Pb1–x Sn x Te and Pb1–x Sn x Se, and nanowires from the bulk crystals using the vapor–liquid–solid (VLS) technique. Nanowires of Pb1–x Sn x Te have been produced with a Sn composition of x = ∼ 0.25, at which a transition from trivial to nontrivial insulator is reported. The results obtained on the growth of nanomaterials of Pb1–x Sn x Se are also described. Detailed characterization of the bulk crystals and the nanomaterials through X-ray diffraction, microscopy techniques, and EDX analysis are presented.
Inelastic neutron scattering (INS) and specific heat measurements have been performed on the intermediate valence compound CeRuSi sub(3), which is isostructural to the noncentrosymmetric ...pressure-induced superconductors CeRhSi sub(3), CeIrSi sub(3), and CeCoGe sub(3). INS measurements at 7 K reveal a broad peak at (58.5 + or - 1.4) meV, while at 300 K, broad quasielastic scattering is observed. This indicates a large Kondo temperature of T sub(K) ~ 680 K. The magnetic contribution to the specific heat (C sub(mag)) has a value of gamma = 62.5 (1) mJ / mol K super(2) at low temperatures and above about 100 K can be well accounted for by the Coqblin-Schrieffer model with a characteristic temperature of T sub(0) = 680 K, which is further evidence that CeRuSi sub(3) is in the intermediate valence regime.
Armour grade quenched and tempered steel closely confirming to AISI 4340 is well known for its superior ballistic performance and hence used in the fabrication of combat vehicles. The traditional ...fillers like austenitic stain- less steel showed poor ballistic performance of these welded joints as compared to the base metal. Attempts have been made to deposit hardfaced interlayer between austenitic stainless steel weld metals. Though this method, mar-- ginal improvements in ballistic performance can be yielded, and cracks were observed in between base metal and hardfaced layer. Thickness of the hardfaced interlayer plays a vital role for the effective ballistic performance. Thus, an attempt has been made to investigate the effect of hardfaced interlayer thickness on ballistic performance of ar- mour steel welds. The results of effect of buttering, low hydrogen ferritic （LHF） filler and three different hardfaced layer thicknesses （4, 5.5 and 7 ram） on ballistid performance of shielded metal arc welded armour steel joints were given.
PDF
