Multiphase magnetism in Yb ₂ Ti ₂ O ₇

Abstract

We use neutron scattering to show that ferromagnetism and antiferromagnetism coexist in the low T state of the pyrochlore quantum magnet Yb2Ti2O7. While magnetic Bragg peaks evidence long-range static ferromagnetic order, inelastic scattering shows that short-range correlated antiferromagnetism is also present. Small-angle neutron scattering provides direct evidence for mesoscale magnetic structure that we associate with metastable antiferromagnetism. Classical Monte Carlo simulations based on exchange interactions inferred from ⟨111⟩-oriented high-field spin wave measurements confirm that antiferromagnetism is metastable within the otherwise ferromagnetic ground state. The apparent lack of coherent spin wave excitations and strong sensitivity to quenched disorder characterizing Yb2Ti2O7 is a consequence of this multiphase magnetism.

Fragmentation in Frustrated Magnets: A Review

“…This is often related to the proximity to a competing phase, or a quantum critical point. In pyrochlores, it is for example the case of Yb 2 Ti 2 O 7 [57][58][59] or Er 2 Sn 2 O 7 [60,61]. However, fragmentation differs from traditional quantum melting since its key point is that the disordered contribution supports an emergent gauge field.…”

Sleuthing out exotic quantum spin liquidity in the pyrochlore magnet Ce$_2$Zr$_2$O$_7$

“…The lack of magnetic ordering and liquid-like structure of neutron scattering response in Ce 2 Zr 2 O 7 4,5 , immediately led to its proposal as the long sought-after QSL known as quantum spin ice. What makes the ceriumbased Ce 2 Zr 2 O 7 pyrochlore distinct from the earlier studied Yb-based quantum spin ice candidate Yb 2 Ti 2 O 7 [7][8][9] is the dipolar-octupolar nature 10 of the ground state doublet of Ce 3+ ion, shown schematically in Fig. 1(a).…”

Field-temperature phase diagram of the enigmatic Nd2(Zr1−xTix)2O7

“…This may be due to the competition at play between the Coulomb phase stabilized above the Néel temperature for thex component and thez-AIAO phase [14,21] (see also Appendix A). This reminds us of the situation in Yb 2 Ti 2 O 7 [17,[38][39][40], where the proximity of competing phases makes the transition temperature extremely sensitive to disorder. In Nd 2 Zr 2 O 7 , the disorder would promote the AIAO ordering at the expense of the Coulomb phase.…”