title: Frustrated spin correlations in diluted spin ice Ho(2-x)La(x)Ti(2)O(7).
abstract: We have studied the evolution of the structural properties as well as the static and dynamic spin correlations of spin ice Ho(2)Ti(2)O(7), where Ho was partially replaced by non-magnetic La. The crystal structure of diluted samples Ho(2-x)La(x)Ti(2)O(7) was characterized by x-ray and neutron diffraction and by Ho L(III)-edge and Ti K-edge extended x-ray absorption fine structure (EXAFS) measurements. It is found that the pyrochlore structure remains intact until about x = 0.3, but a systematic increase in local disorder with increasing La concentration is observed in the EXAFS data, especially from the Ti K edge. Quasi-elastic neutron scattering and ac susceptibility measurements show that, in x≤0.4 samples at temperatures above macroscopic freezing, the spin-spin correlations are short ranged and dynamic in nature. The main difference with pure spin ice in the dynamics is the appearance of a second, faster, relaxation process.
authors.affiliation: Spallation Neutron Source, Oak Ridge National Laboratory, Building 8600, Oak Ridge, TN 37831-6475, USA.
authors.forename: G
authors.initials: G
authors.lastname: Ehlers
authors.forename: E
authors.initials: E
authors.lastname: Mamontov
authors.forename: M
authors.initials: M
authors.lastname: Zamponi
authors.forename: A
authors.initials: A
authors.lastname: Faraone
authors.forename: Y
authors.initials: Y
authors.lastname: Qiu
authors.forename: A L
authors.initials: AL
authors.lastname: Cornelius
authors.forename: C H
authors.initials: CH
authors.lastname: Booth
authors.forename: K C
authors.initials: KC
authors.lastname: Kam
authors.forename: R Le
authors.initials: RL
authors.lastname: Toquin
authors.forename: A K
authors.initials: AK
authors.lastname: Cheetham
authors.forename: J S
authors.initials: JS
authors.lastname: Gardner