South Korean : Strong Diamagnetic or a Superconductor?

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South Korean researchers published papers suggesting they had discovered a room temperature superconductor. However, another paper with resistivity charts shows resistance that is like regular copper. A group in China is reported to have made the LK-99 material and is not getting superconductivity. However, it is early and we are waiting for published results for confirmation. It might just be a strong diamagnetic material. There is more work and study needed to determine and confirm if the hoped for superconductor is confirmed.

Diamagnetism is a property of all materials, and always makes a weak contribution to the material’s response to a magnetic field. However, other forms of magnetism (such as ferromagnetism or paramagnetism) are so much stronger such that, when different forms of magnetism are present in a material, the diamagnetic contribution is usually negligible. Substances where the diamagnetic behavior is the strongest effect are termed diamagnetic materials, or diamagnets. Diamagnetic materials are those that some people generally think of as non-magnetic, and include water, wood, most organic compounds such as petroleum and some plastics, and many metals including copper, particularly the heavy ones with many core electrons, such as mercury, gold and bismuth.

Above – Diamagnetic levitation of pyrolytic carbon

Superconductors may be considered perfect diamagnets because they expel all magnetic fields (except in a thin surface layer) due to the Meissner effect.

Diamagnetism is a property of matter, superconductivity is a state of matter. Diamagnetism describes how a material reacts when plunged into a magnetic field.

Diamagnets may be levitated in stable equilibrium in a magnetic field, with no power consumption. Earnshaw’s theorem seems to preclude the possibility of static magnetic levitation. However, Earnshaw’s theorem applies only to objects with positive susceptibilities, such as ferromagnets (which have a permanent positive moment) and paramagnets (which induce a positive moment).

8 thoughts on “South Korean : Strong Diamagnetic or a Superconductor?”

  1. Even if it is diamagnetism, it’s still an amazing find.it may not solve today’s problems. Coils. However a material that can as effectively absorb fields has many uses.

  4. Diamagnetism does not / would not exhibit any dependance upon Field Cooling or Zero Field Cooling.
    The susceptibility data are quite convincing even though there are a bit difficult to interpret quantitatively since the transition temperature seems to be so ridiculously high (and cannot be reached in their PPMS). Hence the FC and ZFC start from a “unknown” state of the material.

  5. The VA charts in the 1st link are consistent with (near?) zero resistivity with the critical current gradually approaching zero as the temperature is raised towards 400K. I don’t think this can be explained as a simple diamagnet. Of course, this still needs to be replicated.

    • Likewise when the external field is increased.

      If the other group is getting resistance that is like regular copper, it’s possible they failed to get proper mixing and reaction, and are seeing copper inclusions instead.

  6. I was really needing some good news this week. I guess that a false hope is a type of hope. 🤷‍♂️

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