Starting from a top student and marching towards the sea of ​​stars

Chapter 117 My vision is completely different

Based on the performance of various basic tests of this substance, Ning Chen quickly realized that these properties were very different from the predictions in Ning Chen's previous model.

But in any case, being able to synthesize this new type of "potassium-iron-selenium" iron-based substance for the first time is a good achievement.

Next, Ning Chen told Xu Zhou about this result, and Xu Zhou looked very excited after hearing it.

"Ning Chen, how did you synthesize this substance?"

The molecular formula of this substance is K2Fe4Se5, and Xu Zhou knows that this is a substance that has never been artificially synthesized before in the material world.

Regardless of the various properties of this substance, just successfully synthesizing this new substance is enough to publish an SCI.

"Actually, the method is very simple, that is, mix various high-purity raw materials together in a certain proportion, and then sinter them in a solid phase."

This method is the so-called "sintering method" and is a very common method in the field of material synthesis.

Of course, this method seems really simple, but in actual operation, there are many details.

For example, how to proportion the starting raw materials, how to control the degree of grinding of the raw materials, how much the temperature and pressure during the sintering process should be controlled, etc.

If one of the details is not mastered, it will be difficult to synthesize the ideal substance in the end.

Ning Chen also experienced hundreds of failures before gradually figuring out some successful skills and methods.

Xu Zhou carefully checked Ning Chen's measurement data of this new material, and frowned inadvertently.

"Ning Chen, are you going to prepare to measure the superconducting properties of this material next?" Xu Zhou asked.

Because the superconducting critical temperature of superconductors is very low, the measurement of superconductors often uses refrigerants such as liquid helium and liquid nitrogen.

Compared with the measurement of other properties, the measurement of superconducting properties is much more complicated.

"Teacher Xu, this material is most likely not a superconductor."

Ning Chen was very calm when he said this, as if he knew the result long ago.

Seeing Ning Chen say this, Xu Zhou also nodded and said:

"Well, I think so too. Judging from the properties currently measured, the probability that this material is a superconductor is indeed very low."

In fact, Xu Zhou had just come to this conclusion just because Ning Chen had just completed the synthesis of this substance, and Xu Zhou didn't want to pour cold water on Ning Chen.

But seeing that Ning Chen himself was aware of this problem, Xu Zhou no longer had so many worries.

"Teacher Xu, based on the properties of the material we have now obtained, we can determine that there is a vacancy for every five iron atomic positions, and this vacancy exists in the center of the other four iron atoms. From this, we can calculate Out of its composite magnetic moment..."

As Ning Chen spoke, he wrote the entire calculation process on the scratch paper.

"Finally, we calculated that its energy gap is about 300meV. From this, we can judge that this substance is an insulator. Even near absolute zero, there is a high probability that it does not have superconducting properties."

Although in theory, insulators may also have superconducting properties in some special cases, but this possibility is very small.

Ning Chen and Xu Zhou came to this conclusion because this material was different from the model that Ning Chen had constructed before that might have superconducting properties.

"It doesn't matter, Ning Chen. Regardless of whether this material is a superconductor or not, if you can combine it, it is already very powerful. And I suggest you test it again, just in case you can detect any unexpected properties. ?”

"Well, Teacher Xu, I will definitely take a test." Ning Chen nodded.

Ning Chen did not really expect that such an extremely unlikely event would occur, but continuing to complete these measurements would ensure the integrity of the entire experimental process.

In the following time, Ning Chen came to the measurement center and completed the measurement of the superconducting properties of this material.

Unsurprisingly, the material did not exhibit any superconducting properties at low temperatures.

To be more precise, it is even an antiferromagnetic insulator, completely contrary to the properties of a superconductor.

After returning, Ning Chen told Xu Zhou the measurement results, and Xu Zhou made some new discoveries.

"Not bad! This special magnetic structure is very unique. What do you think, do you want to consider writing a paper based on this result? Maybe you can publish a second area, or even a first area!" Previously, Ning Chen might have stopped experimenting and started writing a thesis after being so encouraged by Xu Zhou.

After all, the results of one area and two areas are considered a good result for most researchers.

However, Ning Chen's vision has quietly changed after having published an article in "Nature", three articles in the "Journal of the American Mathematical Society", and won the Simmons Scholar Award.

"Mr. Xu, don't rush to write the paper. I'll see how far I can go with this topic first, and then I will decide how to write the paper and whether to develop it separately."

Blindly splitting the results may affect the value of the entire result.

In addition, Ning Chen's experimental subject is superconductivity and superconducting materials. If he finally publishes a paper on the topic of magnetic structure, Ning Chen himself will feel dumbfounded.

After experiencing this setback, Ning Chen did not continue the experiment immediately. Instead, he analyzed all the experimental data and experimental phenomena obtained so far, and carefully analyzed the reasons.

After thinking about it carefully, Ning Chen also figured out the problem.

"The reason why no superconductor has been synthesized is because of the iron atom vacancy here. It seems that I still have a big problem with the element ratio."

In previous experiments, due to a large number of failures in substance synthesis, Ning Chen was eager to successfully synthesize a new iron-based system of substances.

This made Ning Chen gradually start to adjust the ratio of elements according to the experimental phenomenon, instead of adjusting according to the model established before.

"If you want to truly synthesize a superconductor, you still need to fill the vacancy of this iron atom."

To achieve this goal, the method sounds very simple, which is to increase the proportion of iron.

Of course, in actual operation, there are too many problems involved.

……

After improving the material model, Ning Chen re-adjusted the ratio of each element and continued his experiment.

The next experiment still did not go so smoothly, but Ning Chen was mentally prepared. Even if it failed hundreds or thousands of times in the future, Ning Chen would firmly continue to explore forward.

Unknowingly, time has entered May, and the graduation season is approaching, and the graduation defense of Shengzhou University undergraduates is about to begin.

Because of her special status, Ning Chen did not participate in the previous graduation project, opening defense, mid-term defense, etc., but she still had to participate in the final formal defense.

After all, this is the last hurdle to get the undergraduate degree certificate and graduation certificate. Ning Chen still pays more attention to the defense, so he temporarily stopped the experiment in hand and made various preparations before the defense.

This time, Ning Chen needed to participate in the defense of mathematics and materials at the same time. Of course, Ning Chen had many achievements in these two fields, but when choosing which achievement to use for the defense, Ning Chen still hesitated for a while.

"Hey, let's just use the Sine-Gordon equation in mathematics. If we come up with the three papers that prove Qiu Chengtong's conjecture, it would be a bit overkill."

After all, it was just a graduation defense for undergraduates. If I directly presented the paper in the Journal of the American Mathematical Society, I guess the reviewers might not know what questions to ask.

As for the defense of materials major, Ning Chen thought about it and did not choose the paper he published in "Nature".

Just presenting my research results on porous nano-silica particles is enough to successfully complete my graduation defense.

In the following time, Ning Chen completed the defense PPT of the two results and conducted a rehearsal of the defense process.

After all, there is a time limit for the defense. The time cannot be too short or too long.

Ning Chen could speak well if he went up and gave the lecture without any preparation, but if he accidentally didn't control the time well, it would be very difficult for the reviewer to do the grading work.

At the end of May, the undergraduate graduation defense began.

Ning Chen first participated in the defense of mathematics major.

Ning Chen, a sophomore undergraduate, came to the classroom with a group of seniors and seniors to prepare for the defense.

Although Ning Chen is the youngest in the entire classroom, no one would think that Ning Chen is really their junior.

(End of this chapter)