corner
corner
APS » Journals » Phys. Rev. B » Volume 73 » Issue 17
< Previous Article | Next Article >

Phys. Rev. B 73, 174429 (2006) [6 pages]

Dynamics of diluted Ho spin ice Ho2−xYxTi2O7 studied by neutron spin echo spectroscopy and ac susceptibility

Download: PDF (541 kB) Buy this article Export: BibTeX or EndNote (RIS)

G. Ehlers
SNS Project, Oak Ridge National Laboratory, Building 8600, Oak Ridge, Tennessee 37831-6475, USA

J. S. Gardner
Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA and NIST Center for Neutron Research, NIST, Gaithersburg, Maryland 20899-8562, USA

C. H. Booth and M. Daniel
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

K. C. Kam and A. K. Cheetham
Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA

D. Antonio, H. E. Brooks, and A. L. Cornelius
Physics Department, University of Nevada Las Vegas, Las Vegas, Nevada 89154-4002, USA

S. T. Bramwell and J. Lago
Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom

W. Häussler
FRM II, Lichtenbergstrasse 1, 85747 Garching, Germany

N. Rosov
NIST Center for Neutron Research, NIST, Gaithersburg, Maryland 20899-8562, USA

Received 6 March 2006; published 23 May 2006

We have studied the spin relaxation in diluted spin ice Ho2−xYxTi2O7 by means of neutron spin echo spectroscopy and ac susceptibility measurements. Remarkably, the geometrical frustration is not relieved by doping with nonmagnetic Y, and the dynamics of the freezing is unaltered in the spin echo time window up to x≃1.6. At higher doping with nonmagnetic Y (x≥1.6) a new relaxation process at relatively high temperature (up to at least T≃55 K) appears which is more than 10 times faster than the thermally activated main relaxation process. We find evidence that over the whole range of composition all Ho spins participate in the dynamics. These results are compared to ac susceptibility measurements of the diluted Ho and Dy spin ice systems, which show that at low temperature the Arrhenius behavior is masked by another dynamical process with little temperature dependence. X-ray absorption fine structure (EXAFS) spectra and x-ray diffraction show that the samples are structurally well ordered.

© 2006 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.73.174429
DOI:
10.1103/PhysRevB.73.174429
PACS:
75.40.Gb, 75.25.+z, 75.50.Dd
 
< Previous Article | Next Article >