Electrical properties of materials and their measurement at low temperatures

Fickett, F. R.

doi:10.6028/nbs.tn.1053

Cited by 23 publications

(20 citation statements)

References 51 publications

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“…(One sample with a very low RRR had γ 2 estimated as 3.09.) By comparison, the γ 2 values for aluminum vary between 2 and 5 [ 4 ], whereas the γ 2 values for copper vary between 5 and 6, depending on purity [ 5 ].…”

Section: Temperature Modelsmentioning

confidence: 99%

“…Kohler’s essential observation was that the function ƒ is single-valued over a range of temperatures, increases monotonically, and depends only on the metal and the relative orientation of the field and current. Fickett [ 5 ] observed, regarding Kohler’s rule, that “Very few metals show agreement when wide ranges of temperature, purity, defect concentration, and field are used.” For example, copper follows Kohler’s rule, whereas aluminum does not.…”

Section: The Kohler Relationshipmentioning

confidence: 99%

“…Thus, the difference in the low-temperature R must be related to an intrinsic parameter to be applied to measurements with different voltage tap spacing and cross-sectional area in general. The temperature dependence of the total resistivity ρ ( T ) [ 9 ] is

where ρ p ( T ) is the temperature-dependent intrinsic phonon resistivity and ρ I is the temperature-independent resistivity due to impurities. It is well known that the second term has a small dependence on temperature [ 9 ], but we will ignore this for our first order correction.…”

Section: A First-order Correctionmentioning

confidence: 99%

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A Comparison of Methods for Computing the Residual Resistivity Ratio of High-Purity Niobium

Splett¹,

Vecchia²,

Goodrich³

2011

J. Res. Natl. Inst. Stand. Technol.

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We compare methods for estimating the residual resistivity ratio (RRR) of high-purity niobium and investigate the effects of using different functional models. RRR is typically defined as the ratio of the electrical resistances measured at 273 K (the ice point) and 4.2 K (the boiling point of helium at standard atmospheric pressure). However, pure niobium is superconducting below about 9.3 K, so the low-temperature resistance is defined as the normal-state (i.e., non-superconducting state) resistance extrapolated to 4.2 K and zero magnetic field. Thus, the estimated value of RRR depends significantly on the model used for extrapolation. We examine three models for extrapolation based on temperature versus resistance, two models for extrapolation based on magnetic field versus resistance, and a new model based on the Kohler relationship that can be applied to combined temperature and field data. We also investigate the possibility of re-defining RRR so that the quantity is not dependent on extrapolation.

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Section: Temperature Modelsmentioning

confidence: 99%

Section: The Kohler Relationshipmentioning

confidence: 99%

Section: A First-order Correctionmentioning

confidence: 99%

See 1 more Smart Citation

A Comparison of Methods for Computing the Residual Resistivity Ratio of High-Purity Niobium

Splett¹,

Vecchia²,

Goodrich³

2011

J. Res. Natl. Inst. Stand. Technol.

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“…This resistivity may be as high as 50 10 -m for a Cu-Ni alloy with 40-50 atomic% nickel [14]. In comparison, pure titanium is about 40 10 -m [14]. We believe the formation of a highly resistive barrier coupled with voids results in a very short coherence length, .…”

Section: Discussionmentioning

confidence: 88%

“…The observation of voids at the edges of the pins also suggest that the copper barriers have formed a Cu-Ni alloy barrier with significantly higher resistivity. This resistivity may be as high as 50 10 -m for a Cu-Ni alloy with 40-50 atomic% nickel [14]. In comparison, pure titanium is about 40 10 -m [14].…”

Section: Discussionmentioning

confidence: 92%

The pinning strength and upper critical fields of magnetic and nonmagnetic artificial pinning centers in Nb47/sup W//oTi wires

Motowidlo

Rudziak

Wong

2003

IEEE Trans. Appl. Supercond.

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Nb47 /oTi wire samples were fabricated with copper 12Vol%, 6Ni/6Cu, and 8Ni/4Cu artificial pinning centers (APC). The optimum diameter of the "island" pins was 10 to 12 nm at final wire size. Low temperature heat treatment of sample wires was performed at final diameters to form alloy pins. The upper critical field, 2 , irreversibility field, , and the critical current density, , were measured at 4.2 K. Magnetization measurements showed highest 2 of 11 T and of 9.8 T in the best APC wire. In addition, significant improvement in was obtained at all fields above 5 T compared to past APC designs. At 5 T, s up to 5034 A/mm 2 were obtained by transport measurements. Field emission scanning electron microscopy (FESEM) of the pins at near final wire diameters suggest a new feature. The possible presence of voids formed on the outside of each pin as a result of nickel and copper inter-diffusion (Kirkendall Effect) from low temperature heat treatment.Index Terms-Artificial pinning center, critical current, flux pinning, Nb-Ti wire, proximity effect, upper critical field.

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Enhancement of Carrier Mobility and Bandgap in Plastically Deformed Bi Single Crystal

2023

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Electrical properties of materials and their measurement at low temperatures

Cited by 23 publications

References 51 publications

A Comparison of Methods for Computing the Residual Resistivity Ratio of High-Purity Niobium

A Comparison of Methods for Computing the Residual Resistivity Ratio of High-Purity Niobium

The pinning strength and upper critical fields of magnetic and nonmagnetic artificial pinning centers in Nb47/sup W//oTi wires

Enhancement of Carrier Mobility and Bandgap in Plastically Deformed Bi Single Crystal

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