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We have a new QM website! …and 23+ years of history…

We have a new QM website! …and 23+ years of history…

The first version of the website of our group dates back to February 1997, when Maeno-san was an associate professor under full professor Takehiko Ishiguro. Thanks to the Wayback Machine, we can admire the simple retro look that the website had. The homepage featured the group members on a white...
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Long magnetic penetration depth observed in Sr3−xSnO

Long magnetic penetration depth observed in Sr3−xSnO

Antiperovskite oxide superconductor Sr3−xSnO was measured by a method called muon spin rotation (μSR). It became clear that the magnetic field penetration depth is abnormally long. Sr3−xSnO is a superconductor discovered in our laboratory in 2016. It is the first superconductor in the antiperovskite oxide, and the possibility of topological...
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First virtual QM welcome party

First virtual QM welcome party

We had the first online party of our research group! It was a quite different experience, but we had drinks and food together. The new members introduced themselves and took the chance to tell us something about their hometown and interests. We discovered that Zhongyu Yu is originally from Harbin,...
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“Diamagnetic” signals can appear due to localised heating

“Diamagnetic” signals can appear due to localised heating

Magnetic differential measurements In order to perform magnetisation measurements, it is usually necessary to put a sample onto a sample holder. If the holder magnetization is exactly zero, it is straightforward to extract the sample magnetisation. However, it is practically impossible to bring the holder magnetisation completely to zero. Thus,...
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On the retraction of two papers on current-induced “diamagnetism”

On the retraction of two papers on current-induced “diamagnetism”

Our reports on current-induced "diamagnetism" In 2017, our group reported the insurgence of very large diamagnetism, a phenomenon where a sample shows a magnetisation in the direction antiparallel to the applied magnetic field. The diamagnetism was appearing in the Mott insulator Ca2RuO4 when a current of a few mA was...
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We are a research group in experimental physics at Kyoto University led by Profs. Yoshi Maeno and Kenji Ishida. Our research focuses on various phenomena in strongly correlated materials where strong electron–electron interactions lead to emerging physical properties. These phenomena manifest themselves at temperatures much lower than the ambient one, conditions in which materials are dominated by quantum physics and statistical mechanics. Our main interest involves phenomena such as superconductivity, strong magnetism, and spin ordering effects.

Our group is based on the synergy of two experimental research subgroups: the materials synthesis and characterisation lab led by Prof. Maeno, and the NMR group led by Prof. Ishida. Seminars, scientific discussions, and laboratory activities are conducted jointly by the two groups.

1. Topological superconductors such as Sr2RuO4

Sr2RuO4 is one of the most actively studied superconductors in our laboratory. Our aim is to elucidate the long-standing mystery of its superconducting state by high-purity single crystal growth and precise measurements of electronic transport and magnetism.

2. Material synthesis

New materials are a crucial aspect to discover novel physical phenomena.
In our laboratory, we have succeeded in the synthesis of a large number of materials by the floating zone and flux methods. Notable materials grown in our lab include the superconductor Ag5Pb2O6, the quasi-two-dimensional conductor PdCoO2, the superconductor with broken inversion symmetry CaIrSi3, the new superconductor La3Pt4 and the inverse perovskite oxide superconductor Sr3-xSnO.

3. Microdevices by focused ion beam

We use micro fabrication to reveal new quantum phenomena and study novel material properties.

We also perform studies on small devices, where we can define the material geometry and accurately control the distribution of temperature.

4. Nematic superconductivity

Discovery of nematic superconductivity in CuxBi2Se3, a state in which the superconducting Cooper pairs have a spontaneously broken rotational symmetry.

5. Metal-insulator transitions

We use thermal imaging with materials such as Ca2RuO4 to identify the formation of metallic regions (darker) in a matrix of insulating phase (brighter). This technique allows us to study the formation of metallic regions as a function of current drive.

6. Nuclear magnetic resonance (NMR)

NMR is a powerful measurement tool that allows us to measure electronic and magnetic states on the microscopic scale by using nuclear spins. With this technique, we study the electronic states of a wide range of materials ranging from superconductors to magnetic materials.

7. Uranium-based ferromagnetic superconductivity

For a long time, ferromagnetism and superconductivity were considered to be incompatible. The 5f electrons of uranium compounds, instead, have the special characteristic of being responsible at the same time for both ferromagnetism and superconductivity, two states that are considered to coexist.

We reported several experimental results showing the realisation of a spin triplet state due to ferromagnetic fluctuations in UCoGe.

8. Magnetism and quantum critical phenomena

Several interesting magnetic and superconducting states appear near the quantum critical point of materials. Our research aims to investigate the physical properties near quantum critical points aided by pressure and strong electric and magnetic fields.

9. Quantum size effect in nanoparticles

Nanoparticles can be expected to show unique properties, such as magnetism, metal–insulator transitions, that are due to the discrete nature of the quantum energy levels, which are different from bulk materials. We study quantum size effects in materials such as Pt nanoparticles with NMR measurements.