Chinese Experiments Show Near Room Temperature Superconducting Evidence for LK99

South China University of Technology and Central South University published a paper confirming the discovery of a near-room-temperature superconducting component in LK99-type materials through sample testing. This is significant experimental support for LK99 room temperature superconductivity.

They have found significant hysteresis and memory effect of LFMA in samples of CSLA. The effect is sufficiently robust in magnetic field sweep and rotation and will lose memory in a long duration. The temperature dependence of LFMA intensity exhibits a phase transition at 250 K. The phase diagram of superconducting Meissner and vortex glass is then calculated in the framework of lattice gauge model. In the near future, they will continue to improve the quality of samples to realize full levitation and magnetic flux pinning by increasing active components. The application of a microwave power repository will be considered as well.

Most superconductors have got the low-field microwave absorption (LFMA) due to the presence of superconducting gap and the relevant superconducting vortices as excited states. More importantly, the derivative LFMA of superconductors is positively dependent of the magnetic field as the vortices are more induced under higher field. As a comparison, although the soft magnetism is also active under low field, the precession of spin moments will be suppressed so that the derivative LFMA of magnetic materials is normally negative. The sign of LFMA can be always corrected by the signal of radicals in our measurements. In this case, the signals below 500 Gauss are all positive, implying the presence of superconductivity.

They then sweep the magnetic field forward and backward and observe a prominent hysteresis effect below 450 Gauss, which is independent of the sweep rate. Above this field, the hysteresis is completely absent, excluding the possibility that the positive LFMA and the negative high-field signal together constitute a ferromagnetic resonance (FMR) signal. They guess the negative one refers to a magnetoresistance effect in the normal state. The first turning point and the bifurcation point can be realized as the lower and upper critical field which in this case are 30 and 450 Gauss, respectively.

Strange memory effect of low-field microwave absorption in copper-substituted lead apatite
Jicheng Liu, Chenao He, Weijie Huang, Zhihao Zhen, Guanhua Chen, Tianyong Luo, Xianfeng Qiao, Yao Yao, Dongge Ma

Chinese researchers observe a considerable hysteresis effect of low-field microwave absorption (LFMA) in copper-substituted lead apatite. By continuously rotating samples under external magnetic field, this effect is diminished which can not be renewed by a strong magnetic field but will be spontaneously recovered after two days, indicating its glassy features and excluding possibility of any ferromagnetism. The intensity of LFMA is found to sharply decrease at around 250K, suggesting a phase transition takes place. A lattice gauge model is then employed to assign these effects to the transition between superconducting Meissner phase and vortex glass, and the slow dynamics wherein is calculated as well.

3 thoughts on “Chinese Experiments Show Near Room Temperature Superconducting Evidence for LK99”

  1. Hi Brian,

    Thanks for the experimental news. You are excellent scientist and you publish excellent as outstanding journalist. With respect and gratitude, Reginald

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