The newly synthesized ${\mathrm{Tm}}_2{\mathrm{Ir}}_2{\mathrm{O}}_7$ iridate is investigated using neutron scattering techniques. Powder neutron diffraction patterns confirm that ${\mathrm{Tm}}_2{\mathrm{Ir}}_2{\mathrm{O}}_7$ crystallizes in a cubic structure of pyrochlore type, consistent with the rest of the rare-earth $A_2{\mathrm{Ir}}_2{\mathrm{O}}_7$ series, and the crystal structure is preserved down to 0.2 K. The thermal expansion of the crystal lattice is well described by a Debye model of lattice vibrations. A weak magnetic signal consistent with the so-called all-in-all-out magnetic order (AIAO) is traced at low temperature; however, it cannot serve as unambiguous evidence of the AIAO structure in the compound. Nondispersive magnetic excitations in energy-momentum space are observed in inelastic neutron scattering spectra of ${\mathrm{Tm}}_2{\mathrm{Ir}}_2{\mathrm{O}}_7$. The crystal-field scheme and parameters of the thulium iridate are refined and discussed with respect to the specific heat and magnetization data. The results are supported by mean-field calculations.

• Received 9 March 2022
• Revised 12 August 2022
• Accepted 18 August 2022

DOI:https://doi.org/10.1103/PhysRevB.106.094408