The ilmenite NiTiO3 consists of a buckled honeycomb lattice, with the Ni spins aligned ferromagnetically in-plane and antiferromagnetically out-of-plane. Using neutron spectroscopy, the magnetic structure and the dynamics were investigated as a function of temperature. Dispersive acoustic bands and nearly dispersionless optical bands at ~3.7 meV are described by a highly anisotropy Heisenberg model with stronger antiferromagnetic (AFM) out-of-plane, weaker ferromagnetic (FM) in-plane interactions and an anisotropy gap of 0.95 meV. The order parameter yields a critical exponent between the Heisenberg and two-dimensional Ising models, consistent with highly anisotropic Heisenberg systems. The frustration parameter ~ 2 supports a weakly frustrated system.
@article{arxiv.2509.00513,
title = {Magnetic dynamics in NiTiO3 honeycomb antiferromagnet using neutron scattering},
author = {Srimal Rathnayaka and Luke Daemen and Tao Hong and Songxue Chi and Stuart Calder and John A. Schneeloch and Yongqiang Cheng and Bing Li and Despina Louca},
journal= {arXiv preprint arXiv:2509.00513},
year = {2025}
}