Pressure tuning of structure, superconductivity, and novel magnetic order in the Ce-underdoped electron-doped cuprate T′-Pr_(1.3-x)La_(0.7)Ce_xCuO_4 (x = 0.1)

摘要

High-pressure neutron powder diffraction, muon-spin rotation, and magnetization studies of the structural, magnetic, and the superconducting properties of the Ce-underdoped superconducting (SC) electron-doped cuprate system with the Nd_2CuO_4 (the so-called T′) structure T′-Pr_(1.3-x)La_(0.7)Ce_xCuO_4 with x = 0.1 are reported. A strong reduction of the in-plane and out-of-plane lattice constants is observed under pressure. However, no indication of any pressure-induced phase transition from T′ to the K_2NiF_4 (the so-called T) structure is observed up to the maximum applied pressure of p = 11 GPa. Large and nonlinear increase of the short-range magnetic order temperature T_(so) in T′-Pr_(1.3-x)La_(0.7)Ce_xCuO_4 (x = 0.1) was observed under pressure. Simultaneous pressure causes a nonlinear decrease of the SC transition temperature T_c. All these experiments establish the short-range magnetic order as an intrinsic and competing phase in SC T′-Pr_(1.3-x)La_(0.7)Ce_xCuO_4 (x = 0.1). The observed pressure effects may be interpreted in terms of the improved nesting conditions through the reduction of the in-plane and out-of-plane lattice constants upon hydrostatic pressure.