Possible quantumelectrochemical effects on high Tc superconductors

Pinkowski, A.; Doneit, J.; Jüttner, K.; Lorenz, W.J.; Saemann‐Ischenko, G.; Zetterer, T.; Bréiter, M.W.

doi:10.1016/0013-4686(89)87143-9

Cited by 28 publications

(10 citation statements)

References 25 publications

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“…In addition, a fifth electrode was present, and this was used as the gate electrode (see Supporting Information). Though YBCO has been reported to show robust double layer capacitance which is unchanged before and after emergence of the superconducting state at low temperature,11 there is evidence for room temperature electrochemical reduction of high‐ T c samples in contact with electrolyte, with consequent decrease in T c 12–14. Voltage‐induced modification of the chemical structure and stoichiometry must therefore be taken into account alongside any “pure” field‐effect in devices.…”

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confidence: 99%

Relationship between cognition and awareness of deficit in mild cognitive impairment

Tremont

Alosco

2011

Int J Geriat Psychiatry

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Objective: Although anosognosia is common in Alzheimer's disease (AD), limited research has investigated awareness among patients with mild cognitive impairment (MCI). The current study examined cognitive performance differences between MCI patients who were aware or unaware of their deficits. Methods: Participants were 65 patients who underwent a comprehensive neuropsychological evaluation and diagnosed with MCI according to Petersen's criteria. Participants were divided into groups based on clinician rating of awareness (aware n ¼ 30 or unaware n ¼ 35), which was determined following interview with the patient and family member. Neuropsychological measures were converted into zscores based on sample mean and standard deviation and averaged across cognitive domains. Frontal behavioral ratings were also collected. Results: No significant differences were found between awareness groups for age, education, gender, or MMSE score. Individuals rated as unaware performed significantly worse in the learning domain and a trend for worse performance on the Dementia Rating Scale -II total score than those rated as aware. None of the other cognitive or behavioral domains differed between the groups. Clinician and informant ratings of anosognosia were only modestly correlated, and we found an unexpected pattern of relationships between informant ratings and cognitive performance. Conclusions: Awareness deficits are common in MCI patients. Our results argue against the most common etiologic hypotheses in AD (i.e., executive and right hemisphere) and suggest that severity of encoding deficits underlie anosognosia in MCI.

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confidence: 99%

Relationship between cognition and awareness of deficit in mild cognitive impairment

Tremont

Alosco

2011

Int J Geriat Psychiatry

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“…Tremendous advances in the synthesis of high-temperature superconductors have pushed superconducting critical temperatures (To) above that of liquid nitrogen (-196~ (27, 28). There are no reports on electrochemistry at these new materials in fluid electrolytes at temperatures below their Tc values, but interesting electrochemical effects have been observed at Tc in experiments using solid electrolytes (29)(30)(31). Use of a suitably low temperature fluid electrolyte would improve contact to the superconducting electrode interface (as compared to solid-solid contacts) and could potentially provide access to a greater range of electrochemical reactions and experimental techniques to study the electrochemistry of superconductor electrodes such as YBa2Cu~O7 (T~ = -180~ Bi2Sr2Ca2Cu3010 (Tc = - 163~ and T12Ba2Ca2Cu3010 (To = -148 ~ in their superconducting states.…”

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confidence: 99%

Liquid Phase Electrochemistry at Ultralow Temperatures

Ching

McDevitt

Peck

et al. 1991

J. Electrochem. Soc.

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Fluid electrolyte solutions based on mixtures of butyronitrile (PrCN) and ethyl chloride (EtCl) with Bu4NPF6 or Bu4NClO4 as electrolyte freeze below −180°C and provide excellent media for cryogenic electrochemical experiments. A 1:2 mixture of PrCN and EtCl exhibits the best combination of freezing point and ionic conductivity for ultralow temperature electrochemistry. Diffusion coefficients for bis(pentamethylcyclopentadienyl) iron false(Cp2*normalFefalse) are measurable by potential step chronoamperometry down to −160°C using a conventionally sized electrode, but the resistivity of the solvent mixture is such that potential sweep voltammetry benefits from the use of microdisk (10 and 25 μm diam Pt) or microband (0.2 μm wide Au) electrodes. Voltammetry at a chemically modified electrode down to −170°C is presented for the case of thin films of normalpoly‐false[normalOsfalse(normalbpy)2false(normalvpy)2false]false[PF6]2 .

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“…To conduct electrochemical measurements by using high-Tc electrodes at temperatures below 120 K, a number of formidable technical problems must be overcome. Lorenz and co-workers (28)(29)(30)(31) developed the first successful strategy by using solid electrolyte systems such as Agdoped p"-alumina in contact with a variety of high-Tc ceramic samples. Following potential step excursions, the quasi -dc limits of the resultant current flow across the superconductor-electrolyte interface were monitored as a function of temperature.…”

Section: Electrochemical Techniquesmentioning

confidence: 99%

“…More recent results (31) acquired by using electrochemical impedance spectroscopy with RbAg4I6 / YBaaCugO^* assemblies suggest that both the interfacial charge-transfer resistance and the double-layer capacitance values are slightly reduced at temperatures very close to Tc. Superconducting quantum electrochemical phenomena are thought to be responsible for such effects (28)(29)(30)(31).…”

Section: Electrochemical Techniquesmentioning

confidence: 99%