La2Ni7 is an intermetallic compound that is thought to have itinerant magnetism with a small moment ordering below 65 K. A recent study of single crystal samples by Ribeiro et. al. [Phys. Rev. B 105, 014412 (2022)] determined detailed anisotropic H-T phase diagrams and revealed three zero-field magnetic phase transitions at T1 ~ 61.0 K, T2 ~ 56.5K, and T3 ~ 42 K. In that study only the highest temperature phase is shown to have a clear ferromagnetic component. Here we present a single crystal neutron diffraction study determining the propagation vector and magnetic moment direction of the three magnetically ordered phases, two incommensurate and one commensurate, as a function of temperature. The higher temperature phases have similar, incommensurate propagation vectors, but with different ordered moment directions. At lower temperatures the magnetic order becomes commensurate with magnetic moments along the c direction as part of a first-order magnetic phase transition. We find that the low-temperature commensurate magnetic order is consistent with a proposal from earlier DFT calculations.
@article{arxiv.2203.06341,
title = {Weak itinerant magnetic phases of La2Ni7},
author = {John M. Wilde and Aashish Sapkota and Wei Tian and Sergey L. Budko and Raquel A. Ribeiro and Andreas Kreyssig and Paul C. Canfield},
journal= {arXiv preprint arXiv:2203.06341},
year = {2023}
}
Comments
7 pages, 7 figures Updated magnetic moment size based on data. Discussion is expanded to discuss origin of multiple phase transitions. Several other small changes/additions made throughout the text