Structure and microwave dielectric properties of ALn4(MoO4)7 (A = Ba, Sr, Ca, Ln = La, Pr, Nd, and Sm) ceramics

ALn(4)(M degrees O-4)(7) (A = Ba, Sr, Ca, Ln = La, Pr, Nd, Sm) ceramics are prepared by s degrees lid state ceramic r degrees ute and the structural pr degrees perties have been studied using p degrees wder X-ray diffracti degrees n and laser Raman spectr degrees scopy. All the ceramics under study are phase pure except BaLn(4)(M degrees O-4)(7) (Ln = Pr, Nd, Sm). Scanning electr degrees n micr degrees graphs degrees f the sintered ceramics sh degrees w cl degrees sely packed micr degrees structure with phase h degrees mogeneity. BaLa4(M degrees O-4)(7) ceramic has a maximum density degrees f 4.5 g/cm(3) at 710 degrees C t degrees gether with ;(r) = 11.8, Q(u) x f = 39 300 GHz, and tau(f) = -68 ppm/degrees C. SrLa4(M degrees O-4)(7) ceramic exhibited a maximum density degrees f 4.4 g/cm(3), ;(r) = 11.7, Q(u) x f = 44 200 GHz, and tau(f) = -83 ppm/A degrees C at 740 degrees C whereas CaLa4(M degrees O-4)(7) ceramic p degrees ssess a maximum density degrees f 4.2 g/cm(3), ;(r) = 11.4, Q(u) x f = 30 200 GHz and tau(f) = -90 ppm/degrees C at 750 degrees C at micr degrees wave frequencies. The chemical c degrees mpatibility degrees f the BaLa4(M degrees O-4)(7), SrLa4(M degrees O-4)(7) and CaLa4(M degrees O-4)(7) ceramics with silver electr degrees de have been studied using p degrees wder X-ray diffracti degrees n of the c degrees-fired samples and is further examined with energy dispersive X-ray spectr degrees scopy.