Ionic conduction and ultrasonic velocity in Na1+2xZr2-xMnx(PO4)3

We studied the electrical impedance as a function of frequency ranging from 75 kHz-20 MHz at temperature ranging from 30-253 o C, and the ultrasonic velocity dependence on x at room temperature in order to investigate ionic conduction mechanisms of Na 1-2x Zr 2-x Mn x (PO 4 ) 2 with a bottle-neck structure. In the complex impedance representation, we observed either one or two semicircles strongly dependent on x, and a transition from single semicircle to double semicircles at x=0.5. Ultrasonic velocity showed an anomaly at x=0.5. Based on these results, we concluded that we observed the bulk conduction and grain boundary diffusion of the sodium ion