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arXiv · 1511.02749

Investigation of the magnetic structure and crystal field states of pyrochlore antiferromagnet Nd2Zr2O7

J. Xu·V. K. Anand·A. K. Bera·M. Frontzek·D. L. Abernathy·N. Casati·K. Siemensmeyer·B. Lake
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Abstract

We present synchrotron x-ray diffraction, neutron powder diffraction and time-of-flight inelastic neutron scattering measurements on the rare earth pyrochlore oxide Nd2Zr2O7 to study the ordered state magnetic structure and cystal field states. The structural characterization by high-resolution synchrotron x-ray diffraction confirms that the pyrochlore structure has no detectable O vacancies or Nd/Zr site mixing. The neutron diffraction reveals long range all-in/all-out antiferromagnetic order below T_N ~ 0.4 K with propagation vector k = (0 0 0) and an ordered moment of 1.26(2) μ_B/Nd at 0.1 K. The ordered moment is much smaller than the estimated moment of 2.65 μ_B/Nd for the local <111> Ising ground state of Nd3+ (J=9/2) suggesting that the ordering is partially suppressed by quantum fluctuations. The strong Ising anisotropy is further confirmed by the inelastic neutron scattering data which reveals a well-isolated dipolar-octupolar type Kramers doublet ground state. The crystal field level scheme and ground state wavefunction have been determined.

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J. Xu, V. K. Anand, A. K. Bera, M. Frontzek, D. L. Abernathy, N. Casati, K. Siemensmeyer, B. Lake. 2015-11-09. Investigation of the magnetic structure and crystal field states of pyrochlore antiferromagnet Nd2Zr2O7. https://doi.org/10.1103/physrevb.92.224430

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