Temperature coefficient of resistivity at compositions approaching PdH

Tripodi, P.; McKubre, Michael C. H.; Tanzella, F.; Honnor, P.A.; Gioacchino, D. Di; Celani, F.; Violante, V.

doi:10.1016/s0375-9601(00)00654-x

Cited by 26 publications

(25 citation statements)

References 5 publications

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“…3, are coherent with λ values for x <1 shown in Fig. 2 [6]. This indicates that the other points in Fig.…”

Section: P Dh X : Thermal Coefficient Of Resistance λsupporting

confidence: 77%

“…3 we show further new experimental data demonstrating that with x >1 the coeffi cient λ decreases to lower values, that confi rm the presence of the phase transition between the β and the new γ phase [6]. Experimental method to obtain these results is as follows: in the temperature range between the ice melting temperature T 0 and the water boiling temperature T B , for fi xed stoichiometry x, the temperature coeffi cient of resistance λ can be considered constant, i.e.…”

Section: P Dh X : Thermal Coefficient Of Resistance λsupporting

confidence: 61%

“…Then a steep increase of λ=15000ppm (Fig. 2) has been measured at about x≈1 [6]. This quasi-asymptotic behaviour shown in Fig.…”

Section: P Dh X : Thermal Coefficient Of Resistance λmentioning

confidence: 59%

“…This quasi-asymptotic behaviour shown in Fig. 2 would indicate a possible new phase transition between the β phase and the new γ phase at x=0.95 [6].…”

Section: P Dh X : Thermal Coefficient Of Resistance λmentioning

confidence: 79%

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Magnetic and transport properties of PdH: intriguing superconductive observations

Tripodi

Gioacchino²,

Vinko

2004

Braz. J. Phys.

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Since the discovery of superconductivity in palladium-hydrogen (PdH) and its isotopes (D,T) at low temperature, several efforts have been made to study the properties of this system. Superconductivity of PdH system has been initially claimed by resistance drop versus temperature and then confi rmed by dc magnetic susceptibility measurements. These studies have shown that the critical transition temperature is a function of the hydrogen concentration x in the P dHx system. In all these experiments, the highest concentration x of hydrogen in palladium was lower than the unit. In the last decade we defi ned a room temperature and room pressure technique to load hydrogen and its isotopes into palladium at levels higher than unit, using electrochemical set-up, followed by a stabilization process to maintain the hydrogen concentration in palladium lattice stable. In the meanwhile, several measurements of resistance versus temperature have been performed. These measurements have shown several resistive drops in the range of [18K< Tc < 273K] similar to the results presented in literature, when the superconducting phase has been discovered. Moreover, on PdH wires 6cm long the current-voltage characteristic with a current density greater than 6 * 10 4 Acm −2 has been measured at liquid nitrogen temperature. These measurements have the same behavior as superconducting I-V characteristic with sample resistivity, at 77K, of two orders of magnitude lower than copper or silver at the same temperature. The measurements of fi rst and third harmonic of ac magnetic susceptibility in P dHx system have been performed. These represent a good tool to understand the vortex dynamics, since the superconducting response is strongly non-linear. Clear ac susceptibility signals confi rming the literature data at low temperature (9K) and new signifi cant signals at high temperature (263K) have been detected. A phenomenological approach to describe the resistance behaviour of PdH versus stoichiometry x at room temperature has been developed. The value x=1.6 to achieve a macroscopic superconducting state in P dHx has been predicted.

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“…3, are coherent with λ values for x <1 shown in Fig. 2 [6]. This indicates that the other points in Fig.…”

Section: P Dh X : Thermal Coefficient Of Resistance λsupporting

confidence: 77%

Section: P Dh X : Thermal Coefficient Of Resistance λsupporting

confidence: 61%

“…Then a steep increase of λ=15000ppm (Fig. 2) has been measured at about x≈1 [6]. This quasi-asymptotic behaviour shown in Fig.…”

Section: P Dh X : Thermal Coefficient Of Resistance λmentioning

confidence: 59%

“…This quasi-asymptotic behaviour shown in Fig. 2 would indicate a possible new phase transition between the β phase and the new γ phase at x=0.95 [6].…”

Section: P Dh X : Thermal Coefficient Of Resistance λmentioning

confidence: 79%

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Magnetic and transport properties of PdH: intriguing superconductive observations

Tripodi

Gioacchino²,

Vinko

2004

Braz. J. Phys.

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“…A procedure of this type was developed for H and D loading of long thin Pd wires by Celani 's group at INFN Frascati [13]. This method was further developed collaboratively by Tripodi at SRI for the purpose of measuring temperature effects on resistance [14]. VII.…”

Section: Methodsmentioning

confidence: 99%

USING RESISTIVITY TO MEASURE H/Pd AND D/Pd LOADING: METHOD AND SIGNIFICANCE

McKubre¹,

Tanzella²

2006

Condensed Matter Nuclear Science

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The resistance ratio method is the most frequent technique used to determine the extent of interstitial loading of hydrogen or deuterium atoms into palladium electrodes, or extended structures used in electrolytic or gas phase cold fusion experiments. Specifically, advantage is taken of an empirical relationship between the measured resistance, R, normalized to that of the same body at the same temperature in the absence of hydrogen isotope, R°, hence R/R°, and the atomic fraction occupancy of octahedral interstitials, x = H/Pd or D/Pd. This method was first suggested and employed in cold fusion studies by the present authors [1], and received immediate and widespread acceptance because of the ease with which this experimental technique could be used to make insitu, real-time measurements of a parameter, D/Pd, anticipated [2] or hypothesized [3][4][5][6] at that time to relate to cold fusion heat excess or nuclear production.We take up this topic again 15 years later in an attempt to clear up some errors and misunderstandings regarding the resistance ratio method and its application in cold fusion studies. The relationship between R/R° and x is empirical. That is, calibrations are only as good as the experiments that support the shape of the curve and cannot be used outside the range [P, T, x] in which data are taken. The original calibration [1] (unaccountably and erroneously immortalized as the "famous Baranowski curve") involved an extrapolation of known data into the region of cold fusion interest in the D-Pd system, at x>0.6.Present theory and results focus new attention on the very high loading region as x approaches or even exceeds unity, where double occupation of octahedral sites, tetrahedral site occupancy, new phase formation or new electrical states, may be relevant to the underlying physical process of excess heat and nuclear production. Rather than simply using the resistance ratio as a qualitative tool to determine whether an electrode is better or lesser loaded, it is now important to obtain accurate quantitative information for x close to unity. With further experimentation and analysis of published data it is apparent that the curve originally published in 1990 is in error in the high loading condition. This paper describes how this empirical fit has been improved over the years for both H/Pd and D/Pd by employing new data, new analysis of old data, new experimental methods and results.

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Interactions of Metallic Nanocrystals with Small Molecules

Long

Xiong

2014

Metallic Nanostructures

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Temperature coefficient of resistivity at compositions approaching PdH

Cited by 26 publications

References 5 publications

Magnetic and transport properties of PdH: intriguing superconductive observations

Magnetic and transport properties of PdH: intriguing superconductive observations

USING RESISTIVITY TO MEASURE H/Pd AND D/Pd LOADING: METHOD AND SIGNIFICANCE

Interactions of Metallic Nanocrystals with Small Molecules

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