Magnetic field and pressure effects on charge density wave, superconducting, and magnetic states in Lu${}_5$Ir${}_4$Si${}_{10}$ and Er${}_5$Ir${}_4$Si${}_{10}$

Abstract

We have studied the charge-density-wave (CDW) state for the superconducting Lu${}_5$Ir${}_4$Si${}_{10}$ and the antiferromagnetic Er${}_5$Ir${}_4$Si${}_{10}$ as variables of temperature, magnetic field, and hydrostatic pressure. For Lu${}_5$Ir${}_4$Si${}_{10}$, the application of pressure strongly suppresses the CDW phase but weakly enhances the superconducting phase. For Er${}_5$Ir${}_4$Si${}_{10}$, the incommensurate CDW state is pressure independent and the commensurate CDW state strongly depends on the pressure, whereas the antiferromagnetic ordering is slightly depressed by applying pressure. In addition, Er${}_5$Ir${}_4$Si${}_{10}$ shows negative magnetoresistance at low temperatures, compared with the positive magnetoresistance of Lu${}_5$Ir${}_4$Si${}_{10}$.

12 pages, including 6 figures