Raman studies of phonon anomalies in transition-metal compounds

Klein, Miles V.

doi:10.1007/3540115137_5

Cited by 13 publications

(5 citation statements)

References 73 publications

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“…Due to the coupling of a discrete mode to the continuum BWF line has an asymmetric line shape. 184,191 A Lorentzian line shape given by Eq. 6.2, which belongs to the same family as BWF is used for the D peak:…”

Section: Multi-scale Characterization Of Cathode -Structural and Chemmentioning

confidence: 99%

Multi-Scale Characterization Studies of Aged Li-Ion Large Format Cells for Improved Performance: An Overview

Nagpure

Bhushan

Babu

2013

J. Electrochem. Soc.

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Among various electrical energy storage devices the recent advances in Li-ion battery technology has made this technology very promising for the electric vehicles. The advantage of these batteries is high energy and power density. Understanding the aging mechanisms of these batteries to improve the cycle life is critical for electrification of vehicles. Aging of the cells at the system level is quantified by the increase in internal resistance and drop in capacity. It is imperative to understand the degradation of the electrode materials of the battery related to these system level parameters. The degradation of the material is caused by several simultaneous physiochemical processes that occur within the batteries, which makes material characterization of the electrodes challenging. This review provides results of a systematic multi-scale characterization study to understand the degradation mechanisms in LiFePO 4 cathode material. The study includes various techniques to understand the physical, morphological, electrical, chemical and structural changes in the cathode material. The review also presents an overview of the various modeling techniques used for Li-ion batteries. Simulation results of one of the models are presented using results of multi-scale characterization studies of the cathode material.

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Section: Multi-scale Characterization Of Cathode -Structural and Chemmentioning

confidence: 99%

Multi-Scale Characterization Studies of Aged Li-Ion Large Format Cells for Improved Performance: An Overview

Nagpure

Bhushan

Babu

2013

J. Electrochem. Soc.

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“…antiferromagnetic insulators with strongly correlated electrons. 29,34,39 Spin fluctuations can be probed at the  point of the Brillouin zone, which gives access to magnetic excitons 40 in the case of the multiple spin-wave branches that are typical of systems with coupled spin-orbital excitations. 39,41 Accessible also are the combination bands of magnons and phonons, as in the case of multi-magnon excitations, 42 as well as magnon-phonon combination bands in antiferromagnetic insulators.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of metals, high‐temperature superconductors and related materials under high pressure

Goncharov

Struzhkin

2003

J Raman Spectroscopy

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An overview is presented of recent Raman scattering measurements in metals under conditions of high static pressure in the diamond anvil cell. Also discussed are the practical improvements of the traditional technique that have made these measurements possible. We present the results of several studies including those of hexagonal close-packed (hcp) e-Fe and its solid solutions Fe .1−x/ Ni x (x ≤ 0.2) over a wide temperature range, and also of high-temperature superconductors (YBCO) and their prototypes, i.e. materials with strong electronic correlations such as the 3d metal oxides CoO and FeO.

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“…The role d-electrons play in determining lattice dynamics, electronic and magnetic properties has been of considerable interest in several past decades (Wakabayashi, Scherm et al 1982) (Lockwood 1982) (Klein 1982). Recent activity is related to a tremendous amount of new phenomena (e.g.…”

Section: Why Transition Metals?mentioning

confidence: 99%

Optical Spectroscopy of Strongly Correlated (MOTT-HUBBARD, Heavy-Fermion, Unconventional Superconductor) Materials Tuned Pressure

Goncharov¹,

Struzhkin²

2003

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Funding is requested for systematic experimental studies of pressure-induced changes of electronic, magnetic and structural properties of materials with strong electronic correlations (Mott-Hubbard systems, Kondo insulators, unconventional superconductors) at the Insulator-Metal crossover by optical spectroscopy techniques. Pressure is very important variable allowing to tune critical properties of strongly correlated materials in a controllable and reproducible experimental environment through the I-M transition from low to high temperature conditions. This project benefits from numerous inventions in diamond anvil techniques and optical spectroscopy methods developed over last few years. These include progress in Raman and synchrotron infrared instrumentation permitting studies to higher pressures in unattainable previously energy and wide temperature ranges. Recent theoretical predictions regarding the universal features of the Raman response at the I-M crossover will be tested. This includes the predicted isosbestic point in the in the temperature-dependent Raman response at the insulating side of the transition, and the depletion of low-energy response at low temperature. The experiments will focus on pressure effects on coupled lattice, magnetic and electronic degrees of freedom in strongly correlated materials in the regime close to the insulator-metal transition. At the I-M crossover the materials can not be described as Fermi-liquids (on the metal side), or as conventional insulators (on the insulator side), thus the proposed experiments will provide fundamental information on quasiparticle responses in charge and spin channels. Collapse of magnetic moments under pressure will be studied in great detail by tracing the magnetic excitations in some transition metals and their oxides. High-temperature superconductors (HTS) and other prototype materials (V 2 O 3 , FeSi, and similar classical insulators) will be examined under pressure by Raman spectroscopy in a wide pressure-temperature range on samples with different doping. This will be done to probe various elementary excitations at the I-M crossover: electronic excitations, including pseudogap and superconducting gap excitations, orbital excitations (similar to excitations in LaMnO 3), magnetic excitations and their coupling to phonons. The obtained experimental information will provide a broader impact on theoretical models and new concepts at the frontier of current research of strongly correlated materials. A synchrotron IR technique will be used to study optical properties in far-IR and mid-IR spectral ranges and to identify the free electron component and unconventional excitations. Recently developed high-throughput versatile Raman instrumentation that uses extensively holographic optics will be employed. These studies will use synthetic ultra pure diamonds, which have very low fluorescence. We will also develop a new kind of Raman instrumentation based on volume holographic gratings, and further improve our synchrotron IR facility at the NSLS. One...

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Raman studies of phonon anomalies in transition-metal compounds

Cited by 13 publications

References 73 publications

Multi-Scale Characterization Studies of Aged Li-Ion Large Format Cells for Improved Performance: An Overview

Multi-Scale Characterization Studies of Aged Li-Ion Large Format Cells for Improved Performance: An Overview

Raman spectroscopy of metals, high‐temperature superconductors and related materials under high pressure

Optical Spectroscopy of Strongly Correlated (MOTT-HUBBARD, Heavy-Fermion, Unconventional Superconductor) Materials Tuned Pressure

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