Magnetic properties of the Ising-like rare earth pyrosilicate: D-Er2Si2O7

Gavin Hester; T N DeLazzer; D R Yahne; C L Sarkis; H D Zhao; J A Rodriguez Rivera; S Calder; K A Ross

doi:10.1088/1361-648X/ac136a

Magnetic properties of the Ising-like rare earth pyrosilicate: D-Er₂Si₂O₇

J Phys Condens Matter. 2021 Aug 2;33(40). doi: 10.1088/1361-648X/ac136a.

Authors

Gavin Hester¹, T N DeLazzer¹, D R Yahne¹, C L Sarkis¹, H D Zhao², J A Rodriguez Rivera^{3

4}, S Calder⁵, K A Ross^{1

6}

Affiliations

¹ Department of Physics, Colorado State University, 200 W. Lake St., Fort Collins, CO 80523-1875, United States of America.
² Department of Physics, University of Colorado-Boulder, Boulder, CO 80309, United States of America.
³ NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102, United States of America.
⁴ Department of Materials Science and Engineering, University of Maryland, College Park, MD 20740, United States of America.
⁵ Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America.
⁶ Quantum Materials Program, CIFAR, Toronto, Ontario M5G 1Z8, Canada.

PMID: 34252896
DOI: 10.1088/1361-648X/ac136a

Abstract

Ising-like spin-1/2 magnetic materials are of interest for their ready connection to theory, particularly in the context of quantum critical behavior. In this work we report detailed studies of the magnetic properties of a member of the rare earth pyrosilicate family, D-Er₂Si₂O₇, which is known to display a highly anisotropic Ising-likeg-tensor and effective spin-1/2 magnetic moments. We used powder neutron diffraction, powder inelastic neutron spectroscopy (INS), and single crystal AC susceptibility to characterize its magnetic properties. Neutron diffraction enabled us to determine the magnetic structure below the known transition temperature (T_N= 1.9 K) in zero field, confirming that the magnetic state is a four-sublattice antiferromagnetic structure with two non-collinear Ising axes, as was previously hypothesized. Our powder INS data revealed a gapped excitation at zero field, consistent with anisotropic (possibly Ising) exchange. An applied field of 1 T produces a mode softening, which is consistent with a field-induced second order phase transition. To assess the relevance of D-Er₂Si₂O₇to the transverse field Ising model, we performed AC susceptibility measurements on a single crystal with the magnetic field oriented in the direction transverse to the Ising axes. This revealed a transition at 2.65 T at 0.1 K, a field significantly higher than the mode-softening field observed by powder INS, showing that the field-induced phase transitions are highly field-direction dependent as expected. These measurements suggest that D-Er₂Si₂O₇may be a candidate for further exploration related to the transverse field Ising model.

Keywords: Ising model; inelastic neutron scattering; pyrosilicate; rare earth magnetism.