Magnetic structure ofEr2Ti2O7

Abstract

We employ the previously published neutron scattering experiments [1][2][3] to suggest that Er2Ti2O7 has a broken-symmetry multiple-q state with tetragonal magnetic symmetry [4]. The ordered moments do not appear to lie close to the crystal-field anticipated directions[5] and we suggest that the low energy gapless mode, visible in specific-heat measurements [6], is not of the usual transverse isotropic Goldstone-mode type, but is longitudinal and is associated with the internal transfer of magnetism between distinct magnetic Bragg spots.

Magnetic order, magnetic correlations, and spin dynamics in the pyrochlore antiferromagnet Er2Ti2O7

“…This is consistent with the magnetic structure first proposed by Champion et al, 19 and invalidates the proposal of Ref. 21.…”

“…32 We notice that this description also considered in Refs. 20, 33, and 34 has been recently disputed by Briffa et al 21 In fact the available microscopic information provides an insight into the moment orientation. Let us consider a one-half spin subjected to a molecular field oriented at a polar angle θ from the [111] axis.…”

“…20 The presence of the soft modes has been attributed to the incommensurate value of the canting angle. 21 These astonishing inferences call for more detailed data and analysis. This is the purpose of this work.…”

Low-temperature magnetisation process in the cubic pyrochlore quantum antiferromagnet, Er2Ti2O7

“…Significant progress in the understanding of the properties of Er 2 Ti 2 O 7 has been achieved recently through the theoretical considerations [4,5,17], although not every issue has been resolved to date, as there are alternative descriptions [18] of the magnetism in this compound. One paper [4] explicitly called for additional measurements of the angular dependence of the critical field H c at low temperatures to allow for a more precise identification of the microscopic parameters of the model used in the case of Er 2 Ti 2 O 7 .…”

Measurements of the Heat Capacity of Erbium Titanate Er2Ti2O7

“…In the studies carried out later, the anomaly in question in the low-temperature region was investigated in more detail, which includes the presence of an applied magnetic field. − The theoretical substantiation of the processes occurring while ordering magnetic moments in the structure of the compound is considered in other works. − …”