Improved quality factor of NdNbO4 microwave dielectric ceramic by Mn2+ substitution

(Nd1−xMn1.5x)1.02Nb0.988O4 (x=0.0,0.01,0.02,0.03,0.04,0.05,0.06) microwave dielectric ceramics with improved quality factors were prepared by conventional mixed oxide route. The effects of Mn2+ substitution on the microstructures and microwave dielectric properties of NdNbO4 ceramics were investigated systematically. Microscopic analysis showed that the specimens presented single NdNbO4 phase in the range of x=0.0 to x=0.03, with the substitution content increasing, MnNb2O6 peak appeared in the system. The microwave dielectric properties of NdNbO4 ceramics were strongly dependent on the Mn2+ substitution. An optimal quality factor Q׃=80,000GHz was achieved for (Nd1−xMn1.5x)1.02Nb0.988O4 (x=0.03)ceramics sintered at 1250°C for 4h.