Electronically competing phases and their magnetic field dependence in electron-doped nonsuperconducting and superconducting Pr0.88LaCe0.12CuO4

TL;DR

This study investigates the magnetic phases and their field dependence in electron-doped Pr0.88LaCe0.12CuO4, revealing how magnetic order and superconductivity coexist and respond to magnetic fields through neutron scattering experiments.

Contribution

It provides detailed insights into the magnetic field effects on competing magnetic and superconducting phases in Pr0.88LaCe0.12CuO4, including the spin-flop transition and field-induced order enhancement.

Findings

Magnetic field induces a spin-flop transition in the antiferromagnetic structure.

Superconductivity suppression enhances quasi-2D SDW order.

No effect of magnetic field on 3D AF order in either phase.

Abstract

We present comprehensive neutron scattering studies of nonsuperconducting and superconducting electron-doped Pr0.88LaCe0.12CuO4(PLCCO). At zero field, the transition from antiferromagnetic (AF) as-grown PLCCO to superconductivity without static antiferromagnetism can be achieved by annealing the sample in pure Ar at different temperatures, which also induces an epitaxial (Pr,La,Ce)2O3 phase as an impurity. When the superconductivity first appears in PLCCO, a quasi-two-dimensional (2D) spin-density-wave (SDW) order is also induced, and both coexist with the residual three-dimensional (3D) AF state. A magnetic field applied along the [-1,1,0] direction parallel to the CuO2 plane induces a ``spin-flop'' transition, where the noncollinear AF spin structure of PLCCO is transformed into a collinear one. The spin-flop transition is continuous in semiconducting PLCCO, but gradually becomes sharp with increasing doping and the appearance of superconductivity. A c-axis aligned magnetic field that suppresses the superconductivity also enhances the quasi-2D SDW order at (0.5,0.5,0) for underdoped PLCCO. However, there is no effect on the 3D AF order in either superconducting or nonsuperconducting samples. Since the same field along the [-1,1,0] direction in the CuO2 plane has no (or little) effect on the superconductivity, (0.5,0.5,0) and (Pr,La,Ce)2O3 impurity positions, we conclude that the c-axis field-induced effect is intrinsic to PLCCO and arises from the suppression of superconductivity.