Phase Competition in the Palmer-Chalker XY Pyrochlore Er2Pt2O7

Published

October 30, 2017

Author(s)

A. M. Hallas, J. Gaudet, Nicholas Butch, Guangyong Xu, M. Tachibana, C. R. Wiebe, Graeme M. Luke, Bruce D. Gaulin

Abstract

We report neutron scattering measurements on Er₂Pt₂O₇, a new addition to the XY family of frustrated pyrochlore magnets. Symmetry analysis of our elastic scattering data shows that Er₂Pt_2Od7^ is the first XY pyrochlore to order into the κ = 0,Γ₇ magnetic structure (the Palmer-Chalker state), below Τ_{ν = 0.38 K. This contrasts with its sister XY pyrochlore antiferromagnets Er}d2^Ti₂O₇ and Er₂Ge₂O₇, both of which order into Γ₅ magnetic structures at much higher temperatures, with Τ_{ν=1.2 K and 1.4 K, respectively. Instead, in this temperature range, the magnetic heat capacity of Er}d2^Pt₂O₇ contains a broad anomaly centered at Τ^* = 1.5 K. Our inelastic neutron scattering measurements on Er₂Pt₂O₇ reveal that this broad heat capacity anomaly sets the temperature scale for strong quasi-elastic spin fluctuations. Below Τ_ν = 0.38 K, Er₂Pt₂O₇ displays a gapped spin excitation spectrum with a narrow lower band of excitations, as often occurs in highly frustrated systems. This, in concert with the strong suppression of Τ_{ν, is attributable to phase competition between the Γ}d7^ and Γ₅ states that border each other within a classically predicted phase diagram.

Citation

Physical Review Letters

Volume

119

Issue

18

Pub Type

Journals

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Keywords

neutron scattering pyrochlore magnets frustrated

Citation

Hallas, A. , Gaudet, J. , Butch, N. , Xu, G. , Tachibana, M. , Wiebe, C. , Luke, G. and Gaulin, B. (2017), Phase Competition in the Palmer-Chalker XY Pyrochlore Er₂Pt₂O₇, Physical Review Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=924426 (Accessed April 18, 2024)