Development of Electrode Fabricated DAC and Physical Properties of Layered Nickel Oxide Superconductors

Superconductivity was first discovered in metallic systems and has evolved into copper oxides, iron systems, hydrides, and nickel oxides. The metallic, copper oxide, and iron-based systems were discovered first through experiments, while hydride and nickel oxide were discovered first through theory. This is a kind of game change in research. The discovery of superconductivity in hydrides and nickel oxides required high pressure. In other words, theoretical prediction is essential for a labor-intensive experiment such as high pressure. In this article, we will discuss the “electrode fabricated diamond anvil,” an item in the search for superconductivity under high pressure and briefly introduce the recently discovered nickel oxide superconductors.