Synthesis, structure and magnetic properties of the ternary nitride La3V2N6

Using gallium as a flux we were able to synthesize the rare earth – transition metal ternary nitride La 3 V 2 N 6 . This compound crystallizes in the tetragonal space group I 4/ mmm (No. 139) with a = b =3.9050(3) Å and c =20.215(2) Å. It is isostructural with the recently discovered ternary nitrides Ln 3 T 2 N 6 (Ln=La, Ce or Pr; T=Nb or Ta) and with the high T c superconducting copper oxide La 2− x Sr x CaCu 2 O 6 . LAPW band structure calculations show that Ln 3 V 2 N 6 contains VN 2 conducting layers. However, magnetic measurements show that La 3 V 2 N 6 is not a high T c superconductor. A comparison between Ln 3 V 2 N 6 and the cuprates is attempted to understand the discrepancy in their electronic behavior. Graphic