All Superconductors Absorb Microwaves is Evidence Supporting LK99 As Room Temperature Superconductor

Chinese universities and research labs have published experimental evidence in support of LK99 as a room temperature superconductor. The amount of superconducting material that is made in pile of LK99 powder is small. The LK99 needs to have precisely located copper and phosphorous. This leaves one dimensional molecular chains of superconducting material.

All previous superconductors have been found to absorb microwaves. It is the nature of superconducting material that they exclude magnetic fields and thus the electronic and magnetic behavior is observed based on interaction with microwaves.

Above- A pictorial representation of a Josephson junction in which fluxoids move or are pinned and quasiparticles in the “middle” material (insulator, conductor, semiconductor) move and oscillate. There are impurities, and the cores of the vortices contain normal electrons, and the core behaves as a normal electromagnetic medium (𝜀, 𝜇, 𝜎). The Cooper pairs are present abundantly on both superconductors and tunnel frequently at the middle.

Microwaves have been used to analyze the early samples of new superconductors so that groups learn how to improve the purity and effectiveness of superconductor synthesis.

The original paper from the Chinese researchers is here.

As suggested by Lee et al., the structure of CSLA possesses two circles: The outer circle serves as a shield to protect the inner one which forms a quasi-one-dimensional (1D) conducting channel Lee et al. (2023a, b). The essential idea is to substitute the outer lead atoms with copper to shrink the whole structure. This 1D superconductivity model can be well applied to explain the anisotropic levitation posting on the social media and thus greatly inspires us to uncover the possible 1D strongly-correlated mechanism with a magnetic flux. Previously, we have reported that the cuprate radicals in CSLA hold sufficiently long coherence time to be quantum manipulated Liu et al. (2023b), which yields a useful hint for a successful synthesis. So far, only the powder of mixture has manifested possible superconducting features, so normal electric and magnetic measurements are not available in the current stage. Learnt from the research history of other superconducting materials, such as Y-Ba-Cu-O Blazey et al. (1987); Bhat et al. (1987); Durný et al. (1987); Dulić et al. (1990); Bhat et al. (1991), alkali-metal-doped fullerene Bensebaa et al. (1992), magnesium diboride Bhide et al. (2001); Köseoģlu et al. (2003), and iron pnictides Onyancha et al. (2017), the detection of microwave absorption turns out to be an appropriate approach to determine whether there is superconducting phase in the mixtures, which motivates the main subject of the present work.

Here is a list of major papers on microwave absorption experiments with other types of superconductors.

Physical Review B – Low-field microwave absorption in the superconducting copper oxides. 1987.K. W. Blazey et al.

A nonresonant microwave absorption has been observed at fields below the thermodynamic critical field in the new copper oxide superconductors. This is associated with flux slippage and allows an estimation of the average area of the uniform phase in the superconducting glass state.

Journal of Physics C: Solid State Physics – Absorption of electromagnetic radiation by superconducting YBa2Cu3O7: an oxygen-induced phenomenon Bhat et al. (1987).

In the superconducting state, YBa2Cu3O7 absorbs electromagnetic radiation over a wide range of frequencies (8 MHz-9 GHz). The absorption is extremely sensitive to temperature, particle size and the magnetic field and depends crucially on the presence of oxygen. A possible explanation for the phenomenon based on the formation of Josephson junctions is suggested.

Physical Review B – Microwave absorption in the superconducting and normal phases of Y-Ba-Cu-O Durný et al. (1987).

Microwave absorption in a dc magnetic field up to 12 kG, attributed to nonequilibrium contributions to the ac susceptibility, appears at Tc as the sample is cooled. ESR measurements of Y-Ba-Cu-O show that Cu2+ exists only in the fraction of the sample which is not superconducting in a distorted octahedral surrounding.

Journal of Superconductivity and Novel Magnetism – Temperature Dependence Low-Field Microwave Absorption in a Powder Sample of SmFeAs(O,F) Iron Pnictide Superconductor 2017, R. B. Onyancha.

The effect of temperature variation on low-field microwave absorption (LFMA) was investigated on the SmFeAs(O,F) powder sample of average particle size of ∼3μm in the superconducting region (40K). The two peaks (broad and narrow) which were reported on a pellet of the same sample (Onyancha et al., J. Supercond. Nov. Magn. 28, 2927 (2015)) are observed on the LFMA line shape signal of this powdered sample. It evidently indicates that the peaks are not necessary confined to pellet sample only. Also, the LFMA intensity is found to evolve as a function of temperature. This temperature dependence of the LFMA intensity is interpreted on the framework of effective medium theory in which coupling and decoupling of Josephson junction is considered. Furthermore, we observed an anomalous hysteresis (the LFMA signal in the forward DC field sweep is above the backward DC field sweep) which is consistent with the prediction of the two-level critical state model.

Physica C: Superconductivity – ESR studies on high-Tc superconductor MgB2 Y. Köseoģlu et al 2003.

MgB2, a high-Tc superconductor, has been studied by electron spin resonance (ESR) techniques at the temperature range of 7–300 K. Polycrystalline powders consisting of MgB2, MgO and MgB4 phases were diluted and oriented in paraffin by applying an external magnetic field of 15 kG. A very narrow (2.5 G), strong, and isotropic signal that corresponded to almost free electron g-values was observed at all temperatures. Both the signal intensity and line width were observed to exhibit strong temperature dependence below Tc. The intensity of the ESR spectra, which corresponds to dc susceptibility, generally obeys the Curie law in this temperature range. However, some critical temperatures (approximately 215, 190, 150, and 39 K) were evident from both intensity and line width curves. While the ESR line is strongly broadened, the signal intensity significantly start to increase just below T=39 K (corresponding to a transition temperature from normal to superconducting state), passes through a broad maximum around 30 K and then shows a sharp decrease as the temperature is decreased further. The origins of the minor changes both in the intensity and the line width curves at other (higher) critical temperatures are not clear yet. In fact, the change at 215 K was observed to be meta-stable. These minor changes might be taken as signs for changes of local crystalline field symmetry around weakly localized conduction electrons or holes, which are the sources of the ESR signal.

Superconductor Science and Technology – Magnetic field dependent microwave absorption studies on a MgB2 superconductor Bhide et al 2001.

Polycrystalline MgB2, synthesized using a conventional solid-state reaction route, has been investigated for its magnetic field dependent microwave absorption using a standard X-band EPR spectrometer. The changes in microwave absorption as a function of temperature and/or magnetic field were recorded by following the microwave reflectivity of a sample-loaded cavity. The modulated low-field microwave absorption signal was found to be similar to that observed in high-temperature superconducting materials. The field dependent direct microwave absorption in the 0-10 kG range was used to determine Hc1 values at different temperatures, and the value of Hc1(0) was found to be 250 G. The absorbed microwave power has been found to obey a (H)1/2 dependence with a change of slope indicating a transition from a strongly pinned flux lattice to the flux flow regime.

Physica C: Superconductivity and its Applications – On the origin of low field microwave absorption in the high Tc superconductors

It is shown that the strong signal near zerofield in EPR spectrometric measurements of high Tc superconductors is made up of predominant nonresonant “reflection” of microwaves below Tc under the balanced bridge conditions and a resonant absorption at X-band. The non resonant reflection is associated with the transformation of the compound from Meissner phase to mixed phase. The role of hole trapped oxygen centres in the resonant part of the low field signal was examined by studying the EPR of (CuO+KO2) system. A clear evidence is presented for a low field resonance absorption arising due to exchange interaction of Cu2+ and O− in (CuO+KO2) heated to 473 K.

Superconductors and microwaves.

Superconductivity conforms to a quantum, thermal, and electrodynamic set of physical phenomena of great interest by themselves. They have, also, the potential to be one clean energy source that technology is looking for. Superconductors do not allow static magnetic fields to penetrate them below a critical field, that is, Meissner effect. However, microwave magnetic fields do penetrate them already, and their energy is readily absorbed by the superconductor. High-temperature, perovskite superconductors do absorb microwave energy the most due to the presence of unpaired electron spins, fluxoid dynamics, and quasiparticle motion. We describe the fundamental physics of the interaction of the superconductors with microwaves. Experimental techniques to measure microwave absorption are presented. Experimental setups for absorption of energy are described in terms of the central quantity, Q. The measurements are analyzed in terms of irreversible energy exchange processes. The knowledge gained can inform the design of superconducting devices operating in microwave environments.

Superconductors generate and respond to microwaves: the effect of microwave fields on superconducting tunneling in JJs and on SQCs.

Measurement of absorption of microwaves by superconductors. The experiment, the Q of electromagnetic cavities, the perturbation cavity method
One of the most sensitive measurement techniques to determine absorption of microwaves is the so-called perturbation cavity method. An electromagnetic resonant cavity made of very good conductor, or even superconductor.