Acta Phys. -Chim. Sin. ›› 2003, Vol. 19 ›› Issue (01): 82-84.doi: 10.3866/PKU.WHXB20030119

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Structure and Dielectric Properties of New Tantalates Ba2LaTi2Ta3O15 (Ln=Y, La)

Fang Liang;Zhang Hui;Yan Jun-Bing;Yang Wei-Ming   

  1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology,
  • Received:2002-05-27 Revised:2002-06-17 Published:2003-01-15
  • Contact: Fang Liang E-mail:fangliang001@263.net

Abstract: New tantalates Ba2LnTi2Ta3O15 (Ln=Y, La) were synthesized by Ln partial substitution for Ba in the crystal structure of Ba3TiTa4O15.The crystal structure and dielectric properties were determined by X-ray powder diffraction and dielectric measurements. The results show that Ba2YTi2Ta3O15 belongs to ferroelectric phase of tetragonal tungsten bronze structure at room temperature with unit cell parameters: a=1.236 46(4) nm, c=0.388 60(2) nm. The phase transition of Ba2YTi2Ta3O15 from ferroelectric to paraelectric occurred at 180 ℃. Ba2LaTi2Ta3O15 belongs to paraelectric phase of tetragonal tungsten bronze structure at room temperature with unit cell parameters: a=1.242 64(5) nm, c=0.391 57(2) nm. At room temperature, the dielectric constant (εr) of Ba2YTi2Ta3O15 approached 107, while Ba2LaTi2Ta3O15 ceramic approached 194,combined with a low dielectric loss of 8×10-4 at 1 MHz. Ba2LaTi2Ta3O15 might be a suitable candidate of high εr microwave dielectric ceramics.

Key words: Tantalate, Tungsten bronze structure, XRD, Dielectric property