Insulator to semiconductor transition and magnetic properties of the one-dimensional S = 1/2 system In_2VO_5

TL;DR

This study investigates the insulator-to-semiconductor transition and magnetic properties of In_2VO_5, revealing a crossover from itinerant to localized electron behavior and complex magnetic ordering driven by lattice anisotropy.

Contribution

It provides new insights into the temperature-dependent electronic and magnetic transitions in In_2VO_5, highlighting the role of anisotropic lattice contraction in these phenomena.

Findings

High-temperature ferromagnetic correlations and itinerant electrons.

Transition to insulating behavior with antiferromagnetic interactions below T* ~ 120 K.

Short-range magnetic order at T_SRO ~ 20 K.

Abstract

We report structural, magnetization, electrical resistivity and nuclear- and electron spin resonance data of the complex transition metal oxide In_2VO_5 in which structurally well-defined V-O chains are realized. An itinerant character of the vanadium d-electrons and ferromagnetic correlations, revealed at high temperatures, are contrasted with the insulating behavior and predominantly antiferromagnetic exchange between the localized V^{4+} S = 1/2-magnetic moments which develop below a certain characteristic temperature T* ~ 120 K. Eventually the compound exhibits short-range magnetic order at $T_SRO ~ 20 K. We attribute this crossover occurring around T* to the unusual anisotropic thermal contraction of the lattice which changes significantly the overlap integrals and the character of magnetic intra- and interchain interactions.