Acta Phys. -Chim. Sin. ›› 1989, Vol. 5 ›› Issue (01): 7-9.doi: 10.3866/PKU.WHXB19890103

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The Structure and Phase Transition of Li0.025Na0.975NbO3

Yang Qing-Chuan;Tang You-Qi;Zhong Wei-Lie;Chen Huan-Chu   

  1. Institute of Physical Chemistry, Peking University; Department of Physics, Shandong University
  • Received:1988-09-07 Revised:1988-11-01 Published:1989-02-15
  • Contact: Yang Qing-Chuan

Abstract: Li_(0.025)Na_(0.975)NbO_3 undergoes a ferroelectric-ferroelectric phase transition at 180K (on cooling) or 260 K (on heating). The structure determinations of both phases have been carried out by single crystal diffraction analysis. The ferroelectric room-temperature phase is orthorhombic, with space group Pc2_1b; the cell parameters are a=0.5508(3), b=1.5521(6), c=0.5568(2) nm. The structure is same with Li_(0.02)Na_(0.98)NbO_3. The ferroelectric low-temperature phase is also orthorhomhie, a=0.5497(7), b=0.7913(18), c=0.5565(10) nm, V=0.2421 nm, Z=4. There is disordernal position distribution of O(2) atomes in the low-temperature phase. Its “apparent space group” is P2/n2/n2/n. The relation of the ferroelectric properties to the low-temperature phase structure is discussed.