Tuesday, April 26, 2016

Indications for high Tc superconductivity at 373 K with heff/h=2

Some time ago I learned about a claim of Ivan Kostadinov about superconductivity at temperature of 373 K (100 C). There is also claims by E. Joe Eck about superconductivity: the latest at 400 K. I am not enough experimentalist to be able to decide whether to take the claims seriously or not.

The article of Kostadinov provides a detailed support for the claim. Evidence for diamagnetism (induced magnetization tends to reduce the external magnetic field inside superconductor) is represented: at 242 transition reducing the magnitude of negative susceptibility but keeping it negative takes place. Evidence for gap energy of 15 mV was found at 300 K temperature: this energy is same as thermal energy T/2= 1.5 eV at room temperature. Tape tests passing 125 A through superconducting tape supported very low resistance (for Copper tape started burning after about 5 seconds).

I-V curves at 300 K are shown to exhibit Shapiro steps with radiation frequency in the range [5 GHz, 21 THz]. Already Josephson discovered what - perhaps not so surprisingly - is known as Josephson effect. As one drives super-conductor with an alternating current, the voltage remain constant at certain values. The difference of voltage values between subsequent jumps are given by Shapiro step Δ V= h f/Ze. The interpretation is that voltage suffers a kind of phase locking at these frequencies and alternating current becomes Josephson current with Josephson frequency f= ZeV/h, which is integer multiple of the frequency of the current.

This actually gives a very nice test for heff=n× h hypothesis: Shapiro step Δ V should be scaled up by heff/h=n. The obvious question is whether this occurs in the recent case or whether n=1 explains the findings.

The data represented by Figs. 12, 13,14 of the artcle suggest n=2 for Z=2. The alternative explanation would be that the step is for some reason Δ V= 2hf/Ze corresponding to second harmonic or that the charge of charge carrier is Z=1 (bosonic ion). I worried about a possible error in my calculation several hours last night but failed to find any mistake.

  1. Fig 12 shows I-V curve at room temperature T=300 K. Shapiro step is now 45 mV. This would correspond to frequency f= ZeΔ V/h=11.6 THz. The figure text tells that the frequency is fR=21.762 THz giving fR/f ≈ 1.87. This would suggest heff/h=n ≈ fR/f≈ 2.

  2. Fig. 13 shows another at 300 K. Now Shapiro step is 4.0 mV and corresponds to a frequency 1.24 THz. This would give fR/f≈ 1.95 giving heff/h=2.

  3. Fig. 14 shows I-V curve with single Shapiro step equal to about .12 mV. The frequency should be 2.97 GHz whereas the reported frequency is 5.803 GHz. This gives fR/f≈ 1.95 giving n=2.
Irrespectively of the fate of the claims of Kostadinov and Eck, Josephson effect could allow an elegant manner to demonstrate whether the hierarchy of Planck constants is realized in Nature.

For background see the chapter Quantum Model for Bio-Superconductivity: II.

For a summary of earlier postings see Latest progress in TGD.


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