Self-organized vacancy order in Pr9⁡Ge16

Abstract

In this work, we report the discovery of a new crystal structure on the Ge-rich side of the Pr-Ge binary phase diagram. Using a high-temperature flux technique, we grew single crystals of Pr9⁡Ge16, which adopt a previously unreported orthorhombic 𝐹⁡𝑑⁢𝑑⁢2 structure type featuring ordered Ge vacancies. We present the anisotropic magnetic properties and identify the crystallographic 𝑏 axis perpendicular to the crystal plane as the magnetic easy axis. Temperature-dependent resistivity measurements reveal metallic behavior with a distinct anomaly at 𝑇𝐶 = 14.3 K. Hall resistivity data indicate that electronlike carriers dominate, with a carrier concentration on the order of 1027m−3. The magnetic order is readily suppressed by a magnetic field of approximately 0.4 T applied along the easy 𝑏 axis.