Field-Induced magnetic structures in Tb2Ti2O7 at low temperatures: From spin-ice to spin-flip structures

TL;DR

This study investigates how small misalignments in magnetic field application affect the induced magnetic structures in Tb2Ti2O7, revealing transitions from spin-ice to spin-flip configurations and modeling their behavior.

Contribution

It provides a detailed symmetry analysis and experimental characterization of field-induced magnetic structures in Tb2Ti2O7, highlighting the impact of field alignment on magnetic phases.

Findings

Misalignment influences the magnetic structure type.

Spin-ice-like structures occur with slight misalignment.

A molecular field model explains the k=0 structure evolution.

Abstract

We studied the field-induced magnetic structures of the Tb2Ti2O7 pyrochlore by single-crystal neutron diffraction with a magnetic field applied along a [110] axis, focusing on the influence of a small misalignment. Both induced magnetic structures with k=0 and k=(0,0,1) propagation vectors are found to be sensitive to the misalignment, which controls the magnitude and orientation of the Tb moments involved in the beta chains, with local [111] anisotropy axis perpendicular to the field. For k=0, spin-ice-like structures are observed for a misalignment of a few degrees, whereas other structures, where the Tb-beta moments flip by "melting" on the field axis, occur when the field is perfectly aligned. The field evolution of the k=0 structure is well reproduced by a molecular field model with anisotropic exchange. We give a complete symmetry analysis of the k=0 and k=(0,0,1) magnetic structures, both being described by the basis functions of single irreducible representations.