Masaaki Shimozawa

Dome-shaped magnetic order competing with high-temperature superconductivity at high pressures in FeSe

The coexistence and competition between superconductivity and electronic orders, such as spin or charge density waves, have been a central issue in high transition-temperature (Tc) superconductors. Unlike other iron-based superconductors, FeSe exhibits nematic ordering without magnetism whose relationship with its superconductivity remains unclear. Moreover, a pressure-induced fourfold increase of Tc has been reported, which poses a profound mystery. Here we report high-pressure magnetotransport measurements in FeSe up to ∼15 GPa, which uncover the dome shape of magnetic phase superseding the nematic order. Above ∼6 GPa the sudden enhancement of superconductivity (Tc≤38.3 K) accompanies a suppression of magnetic order, demonstrating their competing nature with very similar energy scales. Above the magnetic dome, we find anomalous transport properties suggesting a possible pseudogap formation, whereas linear-in-temperature resistivity is observed in the normal states of the high-Tc phase above 6 GPa. The obtained phase diagram highlights unique features of FeSe among iron-based superconductors, but bears some resemblance to that of high-Tc cuprates.

Lower critical fields of superconducting PrFeAsO1-y single crystals

We have studied the lower critical fields

Anomalous Upper Critical Field in CeCoIn5/YbCoIn5 Superlattices with a Rashba-type Heavy Fermion Interface

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Controllable Rashba Spin-Orbit Interaction in Artificially Engineered Superlattices Involving the Heavy-Fermion Superconductor CeCoIn[5]

of superconducting iron oxipnictide

Emergence of nontrivial magnetic excitations in a spin-liquid state of kagomé volborthite

{\text{PrFeAsO}}_{1\ensuremath{-}y}

Anomalous Temperature Dependence of Lower Critical Field in Ultraclean URu2Si2

single crystals for

Strong suppression of superconductivity by divalent ytterbium Kondo holes in CeCoIn5

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Quantum-disordered state of magnetic and electric dipoles in an organic Mott system

parallel and perpendicular to the

From Kondo lattices to Kondo superlattices

ab

Tuning the Magnetic Quantum Criticality of Artificial Kondo Superlattices CeRhIn_{5}/YbRhIn_{5}.

planes. Measurements of the local magnetic induction at positions straddling the sample edge by using a miniature Hall-sensor array clearly resolve the first flux penetration from the Meissner state. The temperature dependence of