[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Journal of Physics Condensed Matter: Preface

IN view of the interest attaching to the vaporisation and diffusion of solids, the following observations may be worthy of record.

The Diffusion of Solids

Current-induced effective magnetic fields can provide efficient ways of electrically manipulating the magnetization of ultrathin magnetic heterostructures. Two effects, known as the Rashba spin orbit field and the spin Hall spin torque, have been reported to be responsible for the generation of the effective field. However, a quantitative understanding of the effective field, including its direction with respect to the current flow, is lacking. Here we describe vector measurements of the current-induced effective field in Ta|CoFeB|MgO heterostructrures. The effective field exhibits a significant dependence on the Ta and CoFeB layer thicknesses. In particular, a 1 nm thickness variation of the Ta layer can change the magnitude of the effective field by nearly two orders of magnitude. Moreover, its sign changes when the Ta layer thickness is reduced, indicating that there are two competing effects contributing to it. Our results illustrate that the presence of atomically thin metals can profoundly change the landscape for controlling magnetic moments in magnetic heterostructures electrically.

▲Current-induced effective field vector in Ta│CoFeB│MgO

Study of iron nitride thin films deposited by pulsed laser deposition

Amorphous silicon nitride is a model system for a covalently bound amorphous solid with a low atomic mobility where reasonable values of self-diffusivities are still lacking. We used neutron reflectometry on isotope enriched Si{sub 3} {sup 14}N{sub 4}/Si{sub 3} {sup 15}N{sub 4} multilayers to determine nitrogen self-diffusivities ranging from 10{sup -24} to 10{sup -21} m{sup 2}/s between 950 and 1250 deg. C. Time dependent diffusivities observed at 1150 deg. C indicate the presence of structural relaxation. For long annealing times (relaxed state) the diffusivities follow an Arrhenius law with an activation enthalpy of (3.6{+-}0.4) eV. The results are indicative of a direct diffusion mechanism without the involvement of thermal point defects.

/pdf/nitrogen-diffusion-in-amorphous-silicon-nitride-isotope-9z151jsgdi.pdf

Nitrogen diffusion in amorphous silicon nitride isotope multilayers probed by neutron reflectometry.

Thermal stability of nanometer range Ti/Ni multilayers

The measurement of self-diffusion of iron in amorphous ${\mathrm{FeN}}_{0.7}$ using secondary-ion mass spectroscopy is reported. Diffusion broadening of tracer layers of ${}^{57}{\mathrm{FeN}}_{0.7}$ was observed after isothermal vacuum annealing of the films at different temperatures. Strong structural relaxation effects on diffusion coefficient were observed below crystallization temperature of the amorphous phase. In the well-relaxed state, the values of preexponential factor ${D}_{0}$ and activation energy q are given by $\mathrm{ln}{D}_{0}=\ensuremath{-}16.6\ifmmode\pm\else\textpm\fi{}2{\mathrm{m}}^{2}/\mathrm{s}$ and $q=1.3\ifmmode\pm\else\textpm\fi{}0.2\mathrm{eV}.$ On the basis of correlation between $\mathrm{ln}{D}_{0}$ and q, it is suggested that the mechanism of self-diffusion of iron in amorphous iron nitride is very similar to that in metallic glasses.

Self-diffusion of iron in amorphous iron nitride

/pdf/iron-self-diffusion-in-amorphousfezr-fe57zrmultilayers-20kzfl8qqb.pdf

Mukul Gupta

Papers

Study of iron nitride thin films deposited by pulsed laser deposition

Nitrogen diffusion in amorphous silicon nitride isotope multilayers probed by neutron reflectometry.

Thermal stability of nanometer range Ti/Ni multilayers

Self-diffusion of iron in amorphous iron nitride

Iron self-diffusion in amorphousFeZr∕Fe57Zrmultilayers measured by neutron reflectometry