Structure and magnetic properties of Ba9 V3Te15 with ferromagnetic spin chains

Here we report a ferromagnetic compound Ba9V3Te15 with quasi-one-dimensional (1D) spin chains. It was synthesized at high-temperature and high-pressure conditions and systematically investigated via structural, transport, magnetic and heat capacity measurements. Ba9V3Te15 mainly consists of trimerized face-sharing VTe6 octahedral chains running along the c axis, which are separated by a distance of 10.184(8)Å, thus demonstrating a strong 1D structural character. Ba9V3Te15 is a semiconductor with a band gap ∼128meV and undergoes a ferromagnetic transition with TC∼3.6K. Far above TC, the short-range spin orders due to the intrachain spin coupling have developed, which leads to a negative magnetoresistance effect, the deviation of magnetic susceptibility from the Curie-Weiss law and T1/2 dependence of magnetic heat capacity. Our results reveal that Ba9V3Te15 provides a good opportunity to study the intrinsic properties of a system with quasi-1D ferromagnetic spin chains.