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Showing 1 to 16 of 16 for “"Pnictides"”.
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Thermal expansion and magnetostriction studies on iron pnictides
In this work, a 3-terminal capacitance dilatometer was set up and used for measurements of the thermal expansion and magnetostriction of novel superconducting iron pinictides and related materials. In particular, \re~with R\,=\,La, Ce, Pr, Sm, Gd, \laf~and Ca(Fe$_{1-x}$Co$_x$)$_2$As$_2$ have been …
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Pressure Induced Quantum Phase Transitions in Metallics Oxides and Pnictides
… and compared to those of superconducting pnictides. Antiferromagnetic (AFM) order sets in at ∼125 K with the magnetic moments residing on the Cr site. Pressure measurements are carried out in moissanite and diamond anvil cells in order to suppress the AFM order and resolve the underlying …
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Synthesis, structures, electronic structures and physical properties of quaternary alkali, alkaline earth, rare earth and transition metal pnictides
… is divided into two chapters: (1) quaternary pnictides with complex, noncentrosymmetric structures: Synthesis and Structural Characterization of the New Zintl Phases Na11Ca2Al3Sb 8, Na4CaGaSb3, and Na15Ca3In 5Sb12. In this chapter, three new Zintl phases were represented: Na11Ca2Al3Sb8, …
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Syntheses and studies of group 6 terminal pnictides, early-metal trimetaphosphate complexes, and a new bis-enamide ligand
Investigated herein is the reactivity of the terminal-nitrido, trisanilide tungsten complex, NW(N[i- Pr]Ar)3 (Ar = 3,5-Me 2C6H3, 1). Nitride 1 has been shown to undergo an "N for (O)C1 metathesis with a variety of acid chlorides to form oxochloride (Ar[i-Pr]N) 3W(O)C1 (2) and the corresponding …
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Synthesis and properties of transition-metal arsenide nanostructures: from superparamagnetism to superconductivity
… for synthesis of nanostructured transition-metal pnictides including superconducting LiFeAs and studying their structure- property relationship. Nanostructured materials are known to differ in properties compared to their bulk counterparts owing to enhanced surface area and increased packing …
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Power-law liquid in high-temperature superconductors
… we study the local-itinerant dichotomy in iron pnictides. We show that an interplay between localized moments and itinerant electrons is needed to reproduce the spin excitations observed in inelastic neutron scattering experiments. These results further our understanding of the degrees of …
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Studies in Magnetism and Superconductivity under Extreme Pressure
… and magnetic properties of selected Fe-based pnictides were also studied.
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III-V optoelectronic devices in the BGaInAs material system
… the small lattice constant of the boron pnictides, BGaInAs can be grown lattice-matched or nearly lattice-matched to Si; however, the difficult growth mechanics of elemental boron and the highly mismatched nature of BGaInAs have limited prior synthesis of this alloy to compositions …
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DISORDER EFFECTS IN FRUSTRATED MAGNETS AND ABSORBING STATE TRANSITIONS
… e.g. in cuprate superconductors and iron pnictides. To understand the effects of disorder on such phases, we have investigated the behavior of the diluted J<sub>1</sub>-J<sub>2</sub> Ising model. Spinless impurities generate a random-field disorder for the spin-density (stripe) order …
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Polar intermetallic compounds of the silicon and arsenic family elements and their ternary hydrides and fluorides
… and Z = H, F. Several trivalent rare-earth-metal pnictides, RE5Pn3 (RE = Y, La, Gd, Tb, Dy, Ho, Er, Tm) and alkaline-earth-metal trielides, A5Tr3Zx (Tr = Ga, In, Tl) have been included in an effort to complete observed structural trends. Two main experimental techniques were followed throughout …
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Low Field Microwave Absorption in Nano-Magnetic Participle - incorporated YBa2Cu3O7-z Superconducting Materials
… the unexpected discoveries of cuprates and Fe-pnictides being the dramatic modern examples. Because of their incompatibility, the nucleation of SC near a ferromagnet is di cult and has never been realized except for the case that another superconductor provides proximity-boosted Cooper pairs. …
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Non-perturbative approaches to strongly correlated electron systems
… in the point contact spectroscopy signal on iron pnictides. Chapters 3, 4 and 5 discuss the applications of the AdS/CFT correspondence to model various condensed matter systems. In chapter 3, We consider an interaction term between a bulk spinor field and a gauge field in the Reissner-Nordstr\""om …
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Probing nano-scale atomic and electronic structures of iron-based superconductors
… to the structure families of chalcogenides and pnictides. Crystal structures and bonding have large effects on superconductivity in these materials. Investigating atomic and electronic structures is thus essential to help understand their interesting properties. In this thesis, I have …
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Pnictide und Oxopnictate der schweren Alkalimetalle : Darstellung, Charakterisierung und Kristallchemie
Die Dissertation beschäftigt sich mit der Synthese sowie <br>der strukturellen und spektroskopischen Charkaterisierung <br>neuer Alkalimetallpnictide AxMy und - pnictate AxMyOz. <br> <br>Zahlreiche bisher lediglich aus thermischen Untersuchungen bekannte <br>(z.B. A3M7, A3M11) <br>sowie einige neue …
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High-temperature superconductivity in a family of iron pnictide materials
The work in this thesis falls roughly into three parts, which I characterise loosely as a developmental stage, an exploratory stage, and an attempt to contribute to understanding of the field. In the developmental stage, I have worked to design a variety of methods to create high-quality samples of …
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Orbital order in iron-based superconductors
In this thesis, we propose that a ferro-orbital order, which breaks the degeneracy between the Fe $d_{xz}$ and $d_{yz}$ orbitals, is the effective cause of the structural and the magnetic transitions in the iron-based superconductors. We will discuss this orbital order in the framework of the …