Coexistence of antiferromagnetic order and superconductivity in five-layered Hg-based high- Tc cuprate

Abstract

We report a coexistence of superconductivity and antiferromagnetism in five-layered compound HgBa 2Ca 4Cu 5O y (Hg-1245) with T c=108 K, which is composed of two types of CuO 2 planes in a unit cell, three inner planes (IP) and two outer planes (OP). The Cu-NMR study has revealed that the OP undergoes a superconducting (SC) transition at T c=108 K, whereas three underdoped IPs do an antiferromagnetic (AF) transition below T N∼60 K with the Cu moments of ∼ 0.3–0.4 μ B. The metallic behavior observed at the IP well below T N points to a possibility that SC and AF order parameters coexist in a single CuO 2 plane.