Multiphase Magnetism in Yb2Ti2O7

Abstract

We document the coexistence of ferro- and anti-ferromagnetism in pyrochlore $\mathrm{Y}{\mathrm{b}}_2\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_7$ using three neutron scattering techniques on stoichiometric crystals: elastic neutron scattering shows a canted ferromagnetic ground state, neutron scattering shows spin wave excitations from both a ferro-and an antiferro-magnetic state, and field and temperature dependent small angle neutron scattering reveals the corresponding anisotropic magnetic domain structure. High-field $⟨111⟩$ spin wave fits show that $\mathrm{Y}{\mathrm{b}}_2\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_7$ is extremely close to an antiferromagnetic phase boundary. Classical Monte Carlo simulations based on the interactions inferrred from high field spin wave measurements confirm ${\psi }_2$ antiferromagnetism is metastable within the FM ground state.

11 pages and 11 figures, 8 pages appendices with 10 additional figures