Magnetic Order in YBa₂Cu₃O₆₊ₓ Superconductors

Author

Herbert A. Mook
Pengcheng Dai
Stephen M. Hayden
Arno Hiess
Jeffrey W. Lynn
Seunghun Lee
Fatih Dogan, Missouri University of Science and TechnologyFollow

Abstract

Polarized and unpolarized neutron diffraction has been used to search for magnetic order in YBa₂Cu₃O_6+x superconductors. Most of the measurements were made on a high quality crystal of YBa₂CU₃O_6.6. It is shown that this crystal has highly ordered ortho-II chain order, and a sharp superconducting transition. Inelastic scattering measurements display a very clean spin-gap and pseudogap with any intensity at 10 meV being 50 times smaller than the resonance intensity. The crystal shows a complicated magnetic order that appears to have three components. A magnetic phase is found at high temperatures that seems to stem from an impurity with a moment that is in the a-b plane, but disordered on the crystal lattice. A second ordering occurs near the pseudogap temperature that has a shorter correlation length than the high temperature phase and a moment direction that is at least partly along the c axis of the crystal. Its moment direction, temperature dependence, and Bragg intensities suggest that it may stem from orbital ordering of the d-density wave type. An additional intensity increase occurs below the superconducting transition. The magnetic intensity in these phases does not change noticeably in a 7 T magnetic field aligned approximately along the c axis. Searches for magnetic order in YBa₂Cu₃O₇ show no signal while a small magnetic intensity is found in YBa₂Cu₃O_6.45 that is consistent with the c axis directed magnetic order. The results are contrasted with other recent neutron measurements.

Recommended Citation

H. A. Mook et al., "Magnetic Order in YBa₂Cu₃O₆₊ₓ Superconductors," Physical Review B (Condensed Matter), vol. 66, no. 14, pp. 144513-1 - 144513-10, American Physical Society (APS), Oct 2002.

The definitive version is available at https://doi.org/10.1103/PhysRevB.66.144513

Department(s)

Materials Science and Engineering

Keywords and Phrases

barium derivative; copper derivative; yttrium, crystal; energy; high temperature; magnetic field; magnetism; measurement; neutron; polarization; thermal conductivity

International Standard Serial Number (ISSN)

0163-1829

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2002 American Physical Society (APS), All rights reserved.

Publication Date

01 Oct 2002