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

Author(s):  
J. E. Hirsch

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.

Author(s):  
Jorge Hirsch

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.


Author(s):  
Jorge Hirsch

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.


2003 ◽  
Vol 17 (26) ◽  
pp. 4675-4681 ◽  
Author(s):  
A. V. POP ◽  
M. POP ◽  
I. I. GERU

The effect of partial substitution of Ca by x = 0.02 La on the electrical and magnetically properties of two (Bi,Pb):2223 superconductor ceramic S1 and S2 (with different Pb and Sr atomic concentration) were investigated by using electrical resistance and AC magnetic susceptibility measurements. The parameters from linear resistivity data in the normal state and superconducting transition are sensitive to the compounds stoechiomerty. The intergrain critical current density JcJ(T) dependence near Tc obtained from immaginary AC susceptibility data agrees with the assumption of SNS intergrain junctions.


Author(s):  
Jorge E Hirsch

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.


1988 ◽  
Vol 02 (06) ◽  
pp. 1411-1414 ◽  
Author(s):  
H. C. KU ◽  
C. C. CHEN ◽  
S. W. HSU

Electrical, magnetic and crystallographic measurements have been carried out for the pseudoquaternary ( Nd 1−x Pr x) Ba 2 Cu 3 O 7−δ system. Orthorhombic phase persists from x = 0.0 up to x = 0.7 and transforms into the tetragonal structure only for x ≥ 0.8. Superconducting transition temperature T c decreases linearly from 92 K for x = 0.0 to below 10 K for x = 0.3 and extrapolated to 0 K around x = 0.35. Magnetic susceptibility data indicates that the valence of the Pr ion is close to 4+. Pr 4+ is a very powerful oxidizing agent and may distort or move oxygen away from the Cu-O chain and/or the CuO 2 planes and seriously suppress superconductivity.


Author(s):  
Jorge E Hirsch

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.


2021 ◽  
Vol 7 (7) ◽  
pp. 99
Author(s):  
Linh Trinh ◽  
Eric Rivière ◽  
Sandra Mazerat ◽  
Laure Catala ◽  
Talal Mallah

The collective magnetic behavior of photoswitchable 11 nm cyanide-bridged nanoparticles based of the Prussian blue analogue CsCoFe were investigated when embedded in two different matrices with different concentrations. The effect of the intensity of light irradiation was studied in the less concentrated sample. Magnetization studies and alternating magnetic susceptibility data are consistent with a collective magnetic behavior due to interparticle dipolar magnetic interaction for the two compounds, even though the objects have a size that place them in the superparamagnetic regime.


1989 ◽  
Vol 175 ◽  
Author(s):  
Wolfgang Haase ◽  
Stefan Gehring ◽  
Bettina Borchers

AbstractMagnetic susceptibility data (300–520 K) of monomeric and dimeric mesogenic copper(II) compounds are presented. Different magnetic effects arising from the paramagnetic Cu(II)-centres and the diamagnetic anisotropy of the mesogenic groups are observed and discussed with respect to possible inter molecular interactions.


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