Disconnect between Published AC Magnetic Susceptibility of a Room Temperature Superconductor and Measured Raw Data

10.20944/preprints202112.0115.v1 ◽

2021 ◽

Author(s):

Jorge E Hirsch

Keyword(s):

Magnetic Susceptibility ◽

Room Temperature ◽

Published Data ◽

Ac Magnetic Susceptibility ◽

Raw Data

In ref. [1], we pointed out that certain anomalies observed in the published data for ac magnetic susceptibility of a room temperature superconductor reported in Nature 586, 373 (2020) [2] would be cleared up once the measured raw data were made available. Part of the measured raw data were recently posted in arXiv:2111.15017 [3]. Here we report the results of our analysis of these raw data and our conclusion that they are incompatible with the published data. Implications of these results to the claim that the material is a room temperature superconductor are discussed.

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Incompatibility of Published ac Magnetic Susceptibility of a Room Temperature Superconductor with Measured Raw Data

10.20944/preprints202112.0188.v2 ◽

2021 ◽

Author(s):

J. E. Hirsch

Keyword(s):

High Pressure ◽

Magnetic Susceptibility ◽

Room Temperature ◽

Superconducting Transition ◽

Ac Magnetic Susceptibility ◽

Raw Data ◽

Magnetic Susceptibility Data ◽

Susceptibility Data ◽

Room Temperature Superconductivity

Room temperature superconductivity has recently been reported for a carbonaceous sulfur hydride (CSH) under high pressure by Snider et al [1]. The paper reports sharp drops in magnetic susceptibility as a function of temperature for five different pressures, that are interpreted as signaling a superconducting transition. Here I question the validity and faithfulness of the magnetic susceptibility data presented in the paper by comparison with the measured raw data reported by two of the authors of ref. [2]. This invalidates the assertion of the paper [1] that the susceptibility measurements support the case for superconductivity in this compound.

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Superconductivity in Carbonaceous Sulfur Hydride: Further Analysis of Relation between Published AC Magnetic Susceptibility Data and Measured Raw Data

10.20944/preprints202201.0003.v1 ◽

2022 ◽

Author(s):

Jorge Hirsch

Keyword(s):

Magnetic Susceptibility ◽

Room Temperature ◽

Measured Data ◽

Ac Magnetic Susceptibility ◽

Raw Data ◽

Magnetic Susceptibility Data ◽

Susceptibility Data

In arXiv:2111.15017v1 [1], Dias and Salamat posted some of the measured data for ac magnetic susceptibility of carbonaceous sulfur hydride, a material that was reported in Nature 586, 373 (2020) [2] to be a room temperature superconductor. They provided additional measured data in arXiv:2111.15017v2 [3]. Here I provide an analysis of these data. The results of this analysis indicate that the claim of ref. [2] that magnetic susceptibility measurements support the conclusion that the material is a room temperature superconductor is not supported by valid underlying data.

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Incompatibility of Published ac Magnetic Susceptibility of a Room Temperature Superconductor with Measured Raw Data

10.20944/preprints202112.0188.v1 ◽

2021 ◽

Author(s):

Jorge Hirsch

Keyword(s):

High Pressure ◽

Magnetic Susceptibility ◽

Room Temperature ◽

Superconducting Transition ◽

Ac Magnetic Susceptibility ◽

Raw Data ◽

Magnetic Susceptibility Data ◽

Susceptibility Data ◽

Room Temperature Superconductivity

Room temperature superconductivity has recently been reported for a carbonaceous sulfur hydride (CSH) under high pressure by Snider et al [1]. The paper reports sharp drops in magnetic susceptibility as a function of temperature for five different pressures, that are interpreted as signaling a superconducting transition. Here I question the validity and faithfulness of the magnetic susceptibility data presented in the paper by comparison with the measured raw data reported by two of the authors of ref. [2]. This casts doubt on the assertion of the paper [1] that the susceptibility measurements support the case for superconductivity in this compound.

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Structural Characterization of Co70-xNixGa30 Ferromagnetic Shape Memory Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.52.103 ◽

2008 ◽

Vol 52 ◽

pp. 103-108 ◽

Cited By ~ 3

Author(s):

Sidananda Sarma ◽

A. Srinivasan

Keyword(s):

Magnetic Susceptibility ◽

Shape Memory ◽

Room Temperature ◽

Structural Parameters ◽

Ac Magnetic Susceptibility ◽

X Ray Diffraction ◽

Ferromagnetic Shape Memory Alloys ◽

Two Phase ◽

X Ray ◽

Ferromagnetic Shape Memory

Polycrystalline ingots of Co70–xNixGa30 (20 ≤ x ≤ 26) ferromagnetic shape memory alloy (FSMA) were prepared by arc melting elemental powders followed by homogenization at 1230 °C for 24 hrs and quenching in liquid nitrogen. Room temperature X-Ray diffraction (XRD) patterns of as-quenched samples exhibited single-phase tetragonal structure for alloy compositions with x = 21 to 26, and a two-phase structure (cubic A2-phase along with weak tetragonal phase) for the alloy with x = 20. Rietveld refinement was performed on the X-ray diffraction patterns to obtain the refined structural parameters. Differential Scanning Calorimeter (DSC) curves recorded from 30 °C to 250 °C revealed martensite-austenite and austenite-martensite transformations in all alloys except the alloy with composition x = 20. Low temperature ac magnetic susceptibility measurements confirmed the existence of martensitic transformations in the alloy with x = 20. The structural transformation temperatures show a linear variation with e/a ratio. All the alloys were ferromagnetic at room temperature. Curie temperature was determined using a high temperature ac magnetic susceptibility measurement set-up.

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PRESSURE EFFECT ON CONDUCTIVITY IN Au(dmit)2 LANGMUIR–BLODGETT FILMS

International Journal of Nanoscience ◽

10.1142/s0219581x02000784 ◽

2002 ◽

Vol 01 (05n06) ◽

pp. 627-630 ◽

Cited By ~ 1

Author(s):

YASUHIRO F. MIURA ◽

SHIN-ICHI MORITA ◽

SHIN-HACHIRO SAITO ◽

MICHIO SUGI ◽

MASATO HEDO ◽

...

Keyword(s):

Magnetic Susceptibility ◽

Room Temperature ◽

Pressure Effect ◽

Ambient Pressure ◽

Superconducting Phase ◽

Ac Magnetic Susceptibility ◽

Temperature Resistance ◽

Langmuir Blodgett ◽

Langmuir Blodgett Films ◽

Resistance Decrease

The resistance of the Langmuir–Blodgett films of ditetradecyldimethylammonium- Au(dmit) 2( 2C 14- Au(dmit) 2) salt has been measured under hydrostatic pressure up to 0.7 GPa. The room-temperature resistance decreases with increasing pressure, reaching a 0.6-times smaller value compared to that at ambient pressure. The film under the pressure shows a clear resistance decrease below 1.4 K on cooling, while that under ambient pressure shows a blunt decrease below 0.85 K and it turns to increase below 0.65 K. These results suggest the existence of the pressure-induced superconducting phase together with the earlier results of the ac magnetic susceptibility measurement.

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