We present an experimental study of the pyrochlore coumpound Nd2Zr2O7 by means of neutron scattering and magnetization measurements down to 90 mK. The Nd3+ magnetic moments exhibit a strong local ⟨111⟩ Ising anisotropy together with a dipolar-octupolar nature, different from the standard Kramers-doublet studied so far. We show that, despite the positive Curie-Weiss temperature, \ndzr\ undergoes a transition around 285 mK towards an all-in−all-out antiferromagnetic state. We establish the (H,T) phase diagram in the three directions of the applied field and reveal a metamagnetic transition around 0.1 T. The strongly reduced ordered magnetic moment as well as the unexpected shape of the magnetization curves demonstrate that Nd2Zr2O7 , is not a standard Ising antiferromagnet. We propose that the peculiar nature of the Nd doublet combined with competing interactions explain these findings.
@article{arxiv.1507.01801,
title = {Fluctuations and all-in$-$all-out ordering in dipole-octupole Nd2Zr2O7},
author = {E. Lhotel and S. Petit and S. Guitteny and O. Florea and M. Ciomaga Hatnean and C. Colin and E. Ressouche and M. R. Lees and G. Balakrishnan},
journal= {arXiv preprint arXiv:1507.01801},
year = {2016}
}