Successive Phase Transitions in R₃Ir₄Sn₁₃ (R: La and Ce) Investigated Using Neutron and X-ray Diffraction

Abstract

Successive phase transitions of R 3 Ir 4 Sn 13 (R: La and Ce) were studied using neutron and x-ray diffraction techniques. A semimetal Ce 3 Ir 4 Sn 13 undergoes three phase transitions: an antiferromagnetic ordering characterized by a propagation vector q M = (1/2, 1/2, 2/5) below 0.6 K, a structural transformation with q S2 = (1/4, 1/4, 1/4) at 2.0 K, and another structural transformation with q S1 = (1/2, 1/2, 0) above room temperature. La 3 Ir 4 Sn 13 was confirmed to be a superconductor below 2.5 K under the q S1 = (1/2, 1/2, 0) structure that also appears above room temperature.