ISSP - The institute for Solid State Physics

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Y. Matsuda Group
Associate Professor
MATSUDA,
Yasuhiro

Research Associate
IKEDA,
Akihiko

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Properties of matters that emerge under ultrahigh magnetic fields are being studied. Ground state of matter can dramatically be changed by applying strong magnetic fields, since spin and kinetic motion of electrons are directly affected by magnetic field. Various kinds of novel phases are expected to emerge in the strong magnetic fields through the phenomena such as formation of nontrivial magnetic structure in low dimensional spin systems, exotic local-itinerant transition in strongly-correlated magnetic compounds, and strong spin-lattice coupling in molecular solids. Recent discovery of the novel θ phase of solid oxygen at over around 120 T is a specific example of the field-induced novel phases; the θ phase realizes due to the field-induced molecular rearrangement from the low temperature antiferromagnetic α phase. At higher fields in the range of 1000 T, exploring unknown high-field ground sates in materials with strong interaction is possible. We have also been developing the techniques for generation of the ultrahigh magnetic fields as well as for various kinds of measurements at such ultrahigh fields.

B-T phase diagram of solid oxygen. The high-field θ phase was discovered by magnetization and optical absorption measurements using destructive pulsed magnetic fields.
(a) Magnetization process and (b) Magnetic field derivative of the magnetization (dM/dB) plotted as a function of magnetic field. Two field-induced transitions are observed at 55 and 102 T, respectively. The semiconductor-metal transition occurs at the lower transition field, and a heavy fermion state is expected to appear between the two transition magnetic fields.

Research Subjects

  1. Electronic state of heavy fermion and valence fluctuating systems at ultrahigh magnetic fields
  2. Ultrahigh magnetic field magnetization process of quantum spin systems
  3. Study of magnetic field-induced phase transition at ultrahigh magnetic fields using magnetic birefringence
  4. Magnetic field-induced structural phase transition in solid oxygen
  5. Magnetic field-induced insulator-metal transition in molecular conductors