Magnetic torque measurements have been performed to investigate the phase transitions of the metallic pyrochlore compound Cd2Re2O7, in which a spin-orbit (SO) interaction leads to unique multipole orders associated with an inversion symmetry breaking. We find that the magnetic torque signals with a fourfold symmetry (τ4- H4) as well as a twofold symmetry (τ2- H2) are significantly enhanced at low temperatures below a structural phase transition temperature (∼200 K). The analyses of the torque curve symmetries show that the τ4 term arises from an even-parity order parameter (OP) with the irreducible representation Eg, whereas the τ2 term from an odd-parity OP with Eu, T1u or T2u. The parity mixing of the primary OPs shows a peculiar phase transition in the SO coupled Cd2Re2O7. The coexistence of the two OPs provides important insights into the origin of the multipole orders induced by the SO interaction.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics