  As low as 900 oC, iron-based layered quaternary compound NdFeAsO0.75 was
synthesized through solid state reaction method. XRD measurements illustrate
almost pure phase of tetragonal phase NdFeAsO was formed. The synthesis
temperature in our experiment is the lowest among all the reported methods
without the help of any mineralizer. After further treatment under high
pressure of 6 GPa at temperature of 1300 oC for 2 hours, the electrical
transport property of NdFeAsO0.75 was transformed from insulator-like to metal-
like behavior.
