[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

Rock-salt type niobium nitride ($\delta$-NbN) is a well-known superconductor having superconducting transition temperature (Tc) $\approx$ 18\,K and a large superconducting gap $\approx$3\,meV. The Tc of $\delta$-NbN thin film exhibits a large scattering irrespective of the growth conditions and lattice parameter. In this work, we investigate the atomic origin of suppression of Tc in $\delta$-NbN thin film by employing combined methods of experiments and ab-initio simulations. Sputtered $\delta$-NbN thin films with different disorder were analyzed through electrical resistivity and x-ray absorption spectroscopy. A strong correlation between the superconductivity and the atomic distortion induced electronic reconstruction was observed. The theoretical analysis revealed that under N-rich growth conditions, atomic and molecular N-interstitial defects assisted by cation vacancies form spontaneously and are responsible for the suppression of Tc in $\delta$-NbN by smearing its electronic densities of states around Fermi level.

Microscopic Origin of Structural Disorder in $\delta$-NbN: Correlation of Superconductivity and Electronic Structure

This paper presents asimple route to synthesizesingle phase Nb2N thin film by utilizing the ultra-high vacuum (UHV) rapid thermal annealing (RTA) of ananocrystalline (nc)interstitial Nb(N) thinfilm. The interstitial Nb(N) phase was obtained by reactive sputtering of Nb using a very small amount of N2 in a mixture of Ar and N2 gases. As compared to a reference Nb sample, the nc Nb(N) phase exhibited broadening in the XRD profile, though still retaining the bcc Nb structure. Further, UHV-RTA of Nb(N) at 1023 K results in the formation of single-phase crystalline β-Nb2N phase. Structure and growth characterization of films were carried out and presented in this work.

Synthesis of Nb2N by rapid thermal annealing of interstitial Nb(N) thin film

Different types of defects have been introduced in ferrite thin films and bulk (powder) systems by implementing different methods namely swift heavy ion irradiation, impurity doping.and mechanical milling. Swift heavy ions (190 MeV Au ions and 150 MeV Ni ions) induced defects in nanocrystalline ferrite thin films arise due to formation of the latent tracks and the point defects. We have elaborately discussed the observed effects in magnetic, surface and electrical properties of ferrite thin films irradiated with SHI. The effects of point defects in impurity doping (In ions) and the effects of dislocations in mechanical milling (for different hours) have also been discussed in this paper.

Probing the Effects of SHI and Doping-Induced Defects in Nanocrystalline Spinel Ferrites

The band alignment of Zn0.9Co0.1O/ZnO thin film heterostructure was investigated using photoelectron spectroscopy. The ZnO, Zn0.9Co0.1O and Zn0.9Co0.1O/ZnO thin film heterostructure has been prepared using RF ion beam sputtering, The band offset of prepared heterostructure were calculated form valance band maximum and core level peaks. The valance band and conduction band offset for Zn0.9Co0.1O/ZnO heterostructure thin film were found to be 0.36 eV and 0.51 eV, respectively, which indicates type-II band alignment in the Zn0.9Co0.1O/ZnO heterostructure.

Mukul Gupta

Papers

Microscopic Origin of Structural Disorder in $\delta$-NbN: Correlation of Superconductivity and Electronic Structure

Synthesis of Nb2N by rapid thermal annealing of interstitial Nb(N) thin film

Probing the Effects of SHI and Doping-Induced Defects in Nanocrystalline Spinel Ferrites

Investigation of band alignment in Co doped ZnO/ZnO heterostructure

Experimental and Computational Insights into the Anomalous Thermal Expansion of (Nh4)Reo4,