Spin Waves and Quantum Criticality in the FrustratedXYPyrochlore AntiferromagnetEr2Ti2O7 Academic Article uri icon

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  • We report detailed measurements of the low temperature magnetic phase diagram of Er2Ti2O7. Heat capacity and time-of-flight neutron scattering studies of single crystals reveal unconventional low-energy states. Er3+ magnetic ions reside on a pyrochlore lattice in Er2Ti2O7, where local XY anisotropy and antiferromagnetic interactions give rise to a unique frustrated system. In zero field, the ground state exhibits coexisting short and long-range order, accompanied by soft collective spin excitations previously believed to be absent. The application of finite magnetic fields tunes the ground state continuously through a landscape of noncollinear phases, divided by a zero temperature phase transition at micro{0}H{c} approximately 1.5 T. The characteristic energy scale for spin fluctuations is seen to vanish at the critical point, as expected for a second order quantum phase transition driven by quantum fluctuations.


  • Ruff, JPC
  • Clancy, JP
  • Bourque, A
  • White, MA
  • Ramazanoglu, M
  • Gardner, JS
  • Qiu, Y
  • Copley, JRD
  • Johnson, MB
  • Dabkowska, HA
  • Gaulin, Bruce D

publication date

  • October 3, 2008