Magnetic order in FeGaGe with interlaced quasi-one-dimensional Fe-Chains

We report the crystal growth, structural and physical properties of a rarely explored intermetallic compound FeGaGe. The main feature of its crystal structure is the formation of quasi-one-dimensional Fe chains in the ab-plane that are interlaced when viewed along the c-axis. Magnetization measurements reveal an antiferromagnetic transition at T_N=130 K. Upon further cooling, a susceptibility anomaly occurs at T^*=60 K which can be suppressed under high magnetic field indicating a possible crossover in spin order. Resistivity measurement shows metallic conductivity in FeGaGe with features at both T_N and T^*. Powder neutron diffraction experiment reveals a possible noncollinear spiral antiferromagnetic structure of FeGaGe with periodic spin modulation along the quasi-one-dimensional Fe-chains. Our results establish FeGaGe as a special magnetically ordered system that might host exotic quantum magnetic states.