B4 "High temperature superconductivity"

Staff:

Kenji Ishida (Room 140, Building 5), Shunsaku Kitagawa (Room 139, Building 5)

+ Teaching Assistant (TA)

Introduction
Schedule for the second half of FY2020
Seminar
Experiment content
Report
Recital

Introduction

In this exercise, you will learn basic physical properties related to electrons in solids, such as superconductivity, through experiments and seminars. In fact, it can be said that the behavior of electrons dominates many properties of solids. In solid state physics, various physical phenomena exhibited by various substances are the subject of research, and these phenomena are caused by the influence of a large number of constituent particles (for example, electrons and atoms) on each other. Famous theoretical physicist Philip Anderson’s words More is different. Show that even simple components can interact in a large number to show dramatic behavior that is unexpected in general. This is the real pleasure of solid state physics.

In the experiments of this exercise, we actually synthesize a copper oxide high-temperature superconductor and measure its electrical and magnetic properties at low temperatures. Seminars aim to deepen understanding of electronic physical properties by selecting contents related to experiments. I also want to emphasize the technique of reports and oral presentations as a means to convey the experiments they have conducted to a third party.

Schedule

After the synthesis of YBa₂Cu₃O _7-δ , we will conduct experiments in two groups. Both groups perform experiment “change in superconducting properties due to oxygen deficiency of YBa₂Cu₃O_7-δ “. The seminar will be based on Chapter 10 of “Introduction to Solid State Physics 8th Ed.” By C. Kittel.

Experiment ： Room 6 308

Seminar: on Zoom

Schedule for the second half of 2020 (in Japanese)

Seminar

Superconductivity and magnetism, especially on the following topics.

High temperature superconductivity of copper oxide
Basics of superconductivity

Materials and documents used in seminars will be distributed and designated as needed. Here are some of the things I used in the past:

Introduction to Solid State Physics (C. Kittel)
Solid State Physics (H. Ibach and H. Lüth)
Electronics and Physical Properties (Physical Society of Japan) Chapter 4 [Maruzen]
Strongly correlated electrons and oxides (by Yoshinori Tokura) [Iwanami Shoten]

And so on.

Experiment

Divide into 2 groups and perform material synthesis and physical property measurement at low temperature (electrical resistance and magnetization measurement) (theme may change every year). Synthesis of high temperature superconductor YBa ₂ Cu ₃ O _7- y common to both groups and its superconductivity Group 1

Dependence of superconducting transition temperature on oxygen vacancy y in cuprate high-temperature superconductor YBa ₂ Cu ₃ O _7- y (until the latter half of 2008)
Cu-NQR in copper oxide high temperature superconductor YBa ₂ Cu ₃ O _7- y (first half of FY2009)
Effect of element substitution on superconductivity of high-temperature cuprate YBa ₂ Cu ₃ O _7- y (late 2009)
Changes in crystal structure and superconductivity of YBa ₂ Cu ₃ O _{7-δ due} to oxygen deficiency (2010-2013, 2015-)
Changes in crystal structure and superconductivity due to elemental substitution of YBa ₂ Cu ₃ O _7-δ (2014)
Changes in superconducting properties of YBa ₂ Cu ₃ O _{7-δ due} to oxygen deficiency (2020-)

Group 2

Physical properties of manganese oxides La _2/3 Ca _1/3 MnO ₃ and Nd _1/2 Ca _1/2 MnO ₃ (until the first _{half of} fiscal 2008)
Experiment of superconducting junction using Clark element (late 2008)
Synthesis of layered cuprate high-temperature superconductor Bi ₂ Sr ₂ CaCu ₂ O ₈ whiskers (2009)
Changes in crystal structure and superconductivity of YBa ₂ Cu ₃ O _7-δ by element substitution (2010-)
Changes in superconducting properties of YBa ₂ Cu ₃ O _{7-δ due} to oxygen deficiency (2020-)

In the experiment, we first make YBa ₂ Cu ₃ O _7- y , which is one of the high temperature superconductors of copper oxide . The temperature at which this superconductor becomes superconducting (transition temperature) is relatively high at about 92 Kelvin, so it can be realized by cooling it with liquid nitrogen (about 77 Kelvin). The photo above shows a small magnet (gold) floating on liquid nitrogen cooled YBa ₂ Cu ₃ O _7- y (black). This is also one of the properties of superconductivity.

About reports

Writing a report

When you start a cutting-edge research in the near future, the process of “publishing the contents of your research and the significance of research results as a report or paper and telling others” is the same as the process of issuing data Is very important. Also, even if you do not go on to become a researcher, the skill of writing concise and clear sentences is a necessary skill for any profession. Think of writing a report as “training to develop your writing skills” and try to write a solid report.

The following three points should be paid special attention when writing a report.

Tell accurately
Communicate briefly
Tell the reader to be stress free

You will soon see the need to write “correctly” and “briefly.” In addition to these, although not surprisingly important, the third point of “not stressing the reader” is also important. Not stressing the reader not only makes the text easier to read, but it also eliminates misunderstandings and conveys exactly what you mean.

I want you to be aware of one more point,

Communicating the interest and importance of text content (= research)

That is the point. This is because in the future, there will be many cases where it is necessary to “state the interestingness and importance of research” at various occasions such as writing a paper, writing an application, and finding a job.

Report Structure

It can be said that the standard format of reports for writing “correctly” and “briefly” is almost universal. Here is an example. Title, author name, affiliation summary The content of the research is summarized in a few lines to a dozen lines. It is desirable to have sentences that give you a bird’s eye view of the entire paper. Describe the content of the main research. For example, you may want to set up the following chapters. Background of research, purpose, importance, etc. Means (experimental method) Measuring principle, method, etc. Please use the figure well. Results (experimental results) Measurement data. Use the charts well. Considering what can be said from the results while referring to the literature. Conclusion Summary of research. Future issues, etc. Acknowledgments We would like to express our gratitude to the collaborators and others who have taken care of us. Please write your impressions about the impression experiment and other reports and presentations. I hope to be able to use it as a reference for improving the subject exercises from the next term. Bibliography Appendix (if required)

More detailed information and diagrams of the details of the structure of the report physical English of documents Chapter 2 should also look at.

About the presentation

In this exercise, there will be one small presentation during the semester and one final presentation at the end of the semester. The small presentation is a practice of the presentation, and each group will give a presentation on the synthesis of YBa ₂ Cu ₃ O _7- y and confirmation of superconductivity. At the final presentation, we ask each group to give a presentation on all research contents.

Everyone in each group should share the presentations. In addition, the presentation length should be about 20 minutes for the entire group. The maximum length should be within 30 minutes. After that, there are questions and answers. Usually, it takes about 2 hours as a whole (total of 2 groups).

Basic notes

Of course, the most important thing in the presentation is to convey what you want to convey to the listener. Consider this first. (Note: It is inappropriate to make a presentation that the instructor can understand but the other party’s group cannot understand.) Of course, the content and way of speaking is also important, but here it is the most basic. Here are two possible points:

Considering the overall structure

In this regard, you should have submitted a paper-format report in advance, so you should use that as a baseline. (It is necessary to sort out the contents considering the time limit etc. However, be sure to make only the cover page (including the title and name etc.)

first and the “summary” or “conclusion” page at the end Each page should be easy to understand.

Regarding the second point, please consider the size of the letters and the legibility of the figure. (For example, too small characters or too complicated figures when projected on a projector are inappropriate.) Also, try to use proper colors.