Magnetic properties of AV2O5 (A = Li, Na, Cs, Ca and Mg)

Vanadium oxides with the chemical formula AV(2)O(5) (A = Li, Na, Cs, Ca and Mg) have been synthesized and investigated in terms of low-dimensional quantum spin system. The structure of each compound consists of a characteristic network of VO5 square pyramids formed by sharing edge and/or corner. They were newly found to be spin-gap systems of interests, e.g., new spin-Peierls compound NaV2O5 with T-SP = 35 K, new spin-ladder compounds CaV2O5 and MgV2O5 with a spin gap, a low-dimensional magnet LiV2O5 with an S = 1/2 zig-zag chain and an S = 1/2 dimer system CsV2O5 With a spin gap. The transition from the M-2 to M-1 phase in Al0.01V0.99O2 was proposed to be a spin-Peierls transition. (C) 1998 Elsevier Science B.V. All rights reserved.