Abrupt Negative Thermal Expansion and Magnetic Structure of V3O5

摘要

We report bulk dilatometry and diffraction data throughthe T_(MIT) = 427 K metal-insulator transition of the n = 3 member of theV_nO_(2n-1) Magneli series. Besides VO2, V3O5 is the only other vanadiumoxide with a potentially useful MIT transition above room temperature. Anarrow (AT = 10 K) abrupt negative thermal expansion of a_L = -21.4 ×10~(-6) (dilatometric) and a_v = -213 × 10~(-6) K~(-1) (crystallographic) isobserved. We argue that the combination of the MIT along with thesimultaneous vanadium charge ordering is responsible for such largevalues. The low temperature magnetic properties are also clarified, andneutron diffraction measurements show a k = 1/2 1/2 0 magneticstructure at 1.5 K. DPT calculations of the exchange interactions support the low dimensionality and allow the modeling of themagnetic susceptibility.