Effect of pressure on the superconducting properties and magnetism in HoNi2B2C

The electrical resistance of a single crystal of HoNi2B2C has been measured as a function of temperature (T) and magnetic field (H) under high pressure (P). As pressure increases, TC decreases with the rate of ∂TC/∂P=−0.62  K/GPa but TN increases with ∂TN/∂P=0.41  K/GPa. This implies that the superconductivity above TN competes with antiferromagnetism. The re-entrant superconducting temperature coexisting with the antiferromagnetic phase is increased by applying pressure. The present result indicates that TC coincides with TN near 3.2 GPa.