Syntheses, Crystal Structure and Magnetic Properties of Tl₉<i>RE</i>Te₆ (<i>RE</i> = Ce, Sm, Gd)

• Main Authors: Anna Isaeva, Rico Schönemann, Thomas Doert
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Crystals
• Subjects: Tellurides; thallium; rare-earth metals; crystal structure; magnetic properties
• Online Access: https://www.mdpi.com/2073-4352/10/4/277

The three compounds Tl₉<i>RE</i>Te₆ with <i>RE</i> = Ce, Sm, Gd were synthesized from the elements at 1020 K. Their isostructural crystal structures are ordered derivatives of the Tl₅Te₃ type with rare-earth metal and thallium occupying different Wyckoff positions. The structures can be understood as charge-ordered in accordance with the Zintl-Klemm concept: 9 Tl⁺ + <i>RE</i>³⁺ + 6 Te²⁻. DFT calculations for Tl₉GdTe₆, however, result in a low, but finite density of states at the Fermi level. Magnetic data confirm trivalent Gd, but indicate a small amount of Ce⁴⁺ in Tl₉CeTe₆; no indications for long-range magnetic order was found down to <i>T</i> = 2 K.