Abstract

The superconducting ruthenocuprates RESr2Cu2RuO8 (where RE is a rare earth or Y) have been interpreted as ferromagnetic superconductors, based on a strong response to applied field at the Ru Ńel temperature (around 130 K). However, neutron diffraction measurements on the Gd compound by Lynn [Phys. Rev. B 61, 1214964 (2000)] (using a separated isotope) show evidence only of antiferromagnetic order, while very limited data by Takagiwa [J. Phys. Soc. Jpn. 70, 333 (2001)] on the Y compound show one antiferromagnetic Bragg peak and possible coexisting ferromagnetism. We have studied a sample of YSr2Cu2.1Ru0.9O7.9 prepared by a high pressure-high temperature route. Temperature dependent neutron powder diffraction shows antiferromagnetic order, manifested by the observation of the 1/2, 1/2, 1/2 and 1/2, 1/2, 3/2 reflections, which appear at 135 K [as suggested by the superconducting quantum interference device (SQUID) data]. their intensities at the lowest temperature are consistent with a c -axis orientation of the Ru magnetic moments. Although the lowest order nuclear Bragg peak shows a small intensity increase as the temperature is lowered, this is attributed to magnetic ordering of the Cu planes and not to the presence of a ferromagnetic component, in agreement with the polarized neutron data of Lynn [Phys. Rev. B. 61, 1214964 (2000)] Magnetic resonance and SQUID data on the same sample (to be reported elsewhere) show a complex picture, associated with Cu magnetic ordering. © 2007 American Institute of Physics.

Department(s)

Physics

Publication Status

Available Access

International Standard Serial Number (ISSN)

0021-8979

Document Type

Article - Conference proceedings

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2024 American Institute of Physics, All rights reserved.

Publication Date

21 May 2007

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