TY - JOUR
T1 - Order and disorder in the local and long-range structure of the spin-glass pyrochlore, Tb2Mo2O7
AU - Jiang, Y. U.
AU - Huq, Ashfia
AU - Booth, Corwin H.
AU - Ehlers, Georg
AU - Greedan, John E.
AU - Gardner, Jason S.
PY - 2011/4/27
Y1 - 2011/4/27
N2 - To understand the origin of the spin-glass state in molybdate pyrochlores, the structure of Tb2Mo2O7 is investigated using two techniques: the long-range lattice structure was measured using neutron powder diffraction, and local structure information was obtained from the extended x-ray absorption fine structure technique. While the long-range structure appears generally well ordered, enhanced mean-squared site displacements on the O(1) site and the lack of temperature dependence of the strongly anisotropic displacement parameters for both the Mo and O(1) sites indicate some disorder exists. Likewise, the local structure measurements indicate some Mo-Mo and Tb-O(1) nearest-neighbor disorder exists, similar to that found in the related spin-glass pyrochlore, Y2Mo 2O7. Although the freezing temperature in Tb 2Mo2O7, 25K, is slightly higher than in Y 2Mo2O7, 22K, the degree of local pair distance disorder is actually less in Tb2Mo2O7. This apparent contradiction is considered in light of the interactions involved in the freezing process.
AB - To understand the origin of the spin-glass state in molybdate pyrochlores, the structure of Tb2Mo2O7 is investigated using two techniques: the long-range lattice structure was measured using neutron powder diffraction, and local structure information was obtained from the extended x-ray absorption fine structure technique. While the long-range structure appears generally well ordered, enhanced mean-squared site displacements on the O(1) site and the lack of temperature dependence of the strongly anisotropic displacement parameters for both the Mo and O(1) sites indicate some disorder exists. Likewise, the local structure measurements indicate some Mo-Mo and Tb-O(1) nearest-neighbor disorder exists, similar to that found in the related spin-glass pyrochlore, Y2Mo 2O7. Although the freezing temperature in Tb 2Mo2O7, 25K, is slightly higher than in Y 2Mo2O7, 22K, the degree of local pair distance disorder is actually less in Tb2Mo2O7. This apparent contradiction is considered in light of the interactions involved in the freezing process.
UR - http://www.scopus.com/inward/record.url?scp=79954494897&partnerID=8YFLogxK
U2 - 10.1088/0953-8984/23/16/164214
DO - 10.1088/0953-8984/23/16/164214
M3 - Article
AN - SCOPUS:79954494897
SN - 0953-8984
VL - 23
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 16
M1 - 164214
ER -