Exploring ideal charge-density-wave in superconducting YBCO via innovative uses of X-ray FEL and the pulsed magnet

Increasingly compelling evidence of various forms of non-superconducting electronic orders, such as charge/spin density waves (CDW/SDW), in the cuprate high-T_c superconductors has fundamentally altered our understanding of the essential physics of these materials. However, it has been difficult to establish the nature of the quantum (zero-temperature) phases that compete and/or coexist with superconductivity. In order to overcome this difficulty, it is necessary to destabilize superconducting long-range order at low temperatures by a high magnetic field. In this context, we performed x-ray scattering at an x-ray free electron laser (FEL) in the presence of pulsed high magnetic fields. This approach provides us with the new insight to understand the intertwined phenomena between CDW and SC in YBa₂Cu₃O_x (YBCO) cuprates at magnetic fields, as well as an ideal CDW phase. More details will be touched in this presentation.