After getting the replica experimental data and superconductivity detection data of KL-66 material, Xu Chuan did not make it public as soon as possible.

The Meissner effect has been confirmed to be non-existent in these three sets of controlled replication experiments, and unless subsequent replication experiments conducted by other laboratory research institutions show completely different results, it is enough to preliminarily confirm that KL-66 is not a room-temperature superconductor.

However, Xu Chuan feels that since he wants to do it, he should do it perfectly, so that it is convincing and impeccable.

Once the Meissner effect is confirmed to be non-existent, the key point left is to find out why the material is diamagnetic.

After all, whether it is the video sent by South Korea showing strong diamagnetic performance, or the second group of KL-66 material samples in his reproduction experiment, they all show strong diamagnetism and can float.

Explaining the principle of this is enough to hammer the room-temperature superconductivity properties of this new material.

Of course, the reason why he wants to study this mechanism is not just to make it perfect. It was because of this mechanism that he was curious.

I have to say that there are indeed some problems with the strong diamagnetic mechanism of the KL-66 material developed by South Korea this time.

Judging from the diamagnetic test data of the material of No. 2 KL-66, the reason why it can show the ability to levitate is that some of the copied polycrystalline ceramic samples contain soft ferromagnetic components.

This is the core of its ability to levitate under the application of an external magnetic field.

However, to Xu Chuan's surprise, when the external magnetic field is added to 5T, this soft ferromagnetic component is not saturated.

This means that the material has great potential in terms of diamagnetism.

So even though none of the three sets of replica experiments observed the Meissner effect, he still retained his interest in the material.

After all, there are still many applications of strong diamagnetism, such as magnetic levitation, medical, motors, etc., if a new strong diamagnetic material can be found, there may be an opportunity to replace the expensive superconducting materials originally needed in some fields.

Of course, what interests him more is the principle behind this mechanism.

If the mechanism behind this diamagnetism can be found and applied to the field of real superconducting materials, perhaps he can further increase the critical magnetic field of superconducting materials, and then further compress the volume of controllable nuclear fusion reactors.

This was the main reason why he was really interested in this material.

This material may allow him to find a way to the miniaturization of fusion reactors.

In the laboratory, Xu Chuan found a researcher to assist him in his work, and targeted the diamagnetic test and structural analysis of the No. 2 KL-66 material.

At the same time, a second wave of experiments with KL-66 materials was launched.

However, unlike the first time, this reproduction is not to verify the superconductivity of KL-66 material, but to carry out its diamagnetic effect.

Xu Chuan needs to figure out what happened during the synthesis process, which led to the huge improvement of the soft magnetic effect of the polycrystalline ceramic sample in the No. 2 KL-66 material, and how the corresponding crystal structure, atomic substitution and other things were formed.

It is also necessary to figure out why the same synthesis step, the No. 1 and No. 3 KL-66 materials do not have such a strong diamagnetic effect.

Only when we know these things and confirm the mechanism can we start the next step.

"Boss, the results of the detailed magnetization measurement report are out."

In the office, Chai Su hurried over with a test report.

"I'll see."

Xu Chuan quickly took the test report from the other party and read it carefully.

In physics, the magnetic properties of general materials are divided into several types, such as paramagnetic, diamagnetic, and ferromagnetic.

For example, ferromagnetic materials are put into a magnetic field or dropped below a certain temperature, the material is magnetized, a strong magnetic field is generated, and the material has a clear magnetic pole, such as some materials containing iron, cobalt, nickel and other elements, and the magnetized material can retain ferromagnetism.

Paramagnetic materials, on the other hand, put the material into a magnetic field, and the material is magnetized to produce a smaller magnetic field, which is in the same direction as the original magnetic field and proportional to the original magnetic field, but it will disappear after the external magnetic field is withdrawn.

As for diamagnetic materials, the material is placed in a magnetic field, and the magnetic field generated inside the material is in the opposite direction to the original magnetic field, which will weaken the total magnetic field.

Generally speaking, ferromagnetic materials placed in a magnetic field will be attracted to the original magnetic field, while diamagnetic materials will be repelled by the original magnetic field.

To put it simply, diamagnetism is when two magnets of the same pole are put together, and then you squeeze them with your hands.

The greater the force required to bring them together, the higher the diamagnetism.

Although it is not accurate to say this, it is relatively easy to understand and visual.

Judging from the test report, the magnetic susceptibility of No. 2 KL-66 material is an astonishing -0.8225.

This value, when put into a non-superconducting material, is already very high.

For magnetism, the magnetic susceptibility of the vacuum is 1, which means that the magnetic field in the vacuum is the same as the original magnetic field.

Whereas, the magnetic susceptibility of ordinary diamagnetic materials is negative, but very close to 0. For example, water, some organic matter, and a small amount of metal are all common diamagnetic materials.

The magnetic susceptibility of a superconductor is -1, which is the maximum value of diamagnetism. Significantly different from ordinary diamagnetic materials, it is 100% diamagnetic.

As a result, superconductors repel the external magnetic field very strongly and can firmly bind the magnetic flux lines, whereas ordinary diamagnetic materials only slightly repel the external magnetic field.

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The magnetic flux of 0.8225 is still a certain distance away from the magnetic susceptibility of the superconducting material-1.

But don't forget, the KL-66 material they synthesized is actually not very pure.

If the purity continues to be improved, it is not impossible for the magnetic susceptibility of this material to be infinitely close to that of a superconductor or to be directly filled.

"Interesting, when will the electron microscope structure come out?"

Putting down the report in his hand, Xu Chuan looked at Chai Su and asked.

"I'm already doing it, and it will take about twenty minutes or so." Chai Su replied respectfully.

Nodding, Xu Chuan said, "Okay, report to me as soon as you're done." ”

The amazing magnetic susceptibility really piqued his interest, and it meant that the material, if not a superconductor, had a lot of potential in some ways.

Chai Su nodded, turned around and walked out of the office, and gently closed the door.

Sitting at his desk, Xu Chuan thought about it.

From previous tests of the KL-66 material, he passed the two-band model eg of copper to determine the orbit of the interaction values from the constrained random phase approximation (cRPA).

However, no forced magnetic or orbital symmetry breaks were found in the electron holes of the material.

Whereas, the mechanism that works in the stable insulation state and the level of impurities in the bandgap in two insulators using DFT+U:Cu-doped Pb 10(PO4)6o and V-doped SrTiO3 doped transition metals.

So theoretically, there is an isolated (flat) band of impurities, independent of the doping position. Even under the optimal conditions of superconductivity, spin and orbit fluctuations are too weak for superconductivity close to room temperature.

Because it is almost impossible to exhibit superconductivity at room temperature.

However, when considering diamagnetism, the situation may be different.

Theoretically, in the same unit cell doped with different types of positions, the gap between the materials results in two spin-polarized impurity bands.

And because of the relatively non-localized unpaired spins in the valence band, weak ferromagnetism is possible.

Further work should consider the possibility of further changes in the quantification of stoichiometry, different doping positions, superunit cell effect, and magnetic exchange interactions.

In the office, Xu Chuan silently deduced in his mind, and from time to time he took a pen to perform calculations on the manuscript paper.

The knowledge of materials science in the mind is fused with the information in the fields of physics and chemistry.

If anyone has experienced the moment when he proved the last step of the NS equation in class, he will be familiar with this state.

However, Xu Chuan was the only one in the office, and under the preoccupation of the deduction, he didn't realize that he had returned to the most coveted state today.

It wasn't until a long time passed that Chai Su, who rushed over with the electron microscope structure data, shouted softly, and Xu Chuan came back to his senses.

The illusion of being in a different world made him breathe a long sigh of relief, and when he glanced at the time in the lower right corner of the computer, he realized that nearly half an hour had passed before he knew it.

"Boss, the electron microscope structural data is out." Chai Su swallowed his saliva and reported, why did he feel as if he had done something wrong even though he hadn't done anything?

Xu Chuan nodded and said, "Just put it here." ”

"Okay." Quickly put down the test report in his hand, and Chai Su ran away as soon as he slipped away. Originally, he had some questions he wanted to ask, but suddenly he changed his mind.

Sitting at the desk, Xu Chuan closed his eyes and savored it, and only after half a sound did he lean forward and pick up the electron microscope scanning structure report from the table and flipped through it.

And so it was. At the non-interacting level, KL-66 is an inverted asymmetric Weyl semimetallic material. ”

"Weyl nodes with opposite chirality occur at different energies near the time reversal invariant Γ and at the point of the A-3D Brillouin zone. The unusual Weil charge CW = ±2 and is connected by two branches of the Fermi arc state of topological protection parallel to the surface of the body c-axis. ”

"In other words, in KL-66 material, the spin-orbit coupling of Cu atoms has a crucial impact on the band structure and electronic properties of the material."

Looking at the scan structure diagram and related inspection data, Xu Chuan's eyes showed a look that he had already predicted.

Although he was interrupted by Chai Su, he was not without gains.

Theoretically, the core reason for the strong magnetic properties of KL-66 has been roughly found by inference.

It's just that whether it's accurate or not depends on the follow-up experiments.

Perhaps this time, he can make a complete correlation between strong diamagnetic materials and band topology, and then push the strong correlation physics to a whole new level.

PS: There is another chapter in the evening, asking for a monthly pass.