Structural Studies of Relaxor/Ferroelectric Pb(Mg_1/3Nb_2/3)O₃/PbTiO₃ Superlattices

Abstract

We have synthesized [Pb(Mg_1/3Nb_2/3)O₃]_{(1− x)Λ}/[PbTiO₃] _{x Λ} (PMN_{(1− x)Λ}PT_(x)Λ) superlattices by pulsed laser ablation onto MgO substrates buffered with La_1/2Sr_1/2CoO₃ (LSCO). We varied the composition (0.1 ≤ x ≤ 0.8), and kept the modulation period Λ constant at about 140 ÅX-ray diffraction indicates that the polar c-axis of the PT layers lies in the plane of the films. This is confirmed by the Raman spectra. There is a shift to lower frequencies of the PT soft mode due to stress but we observe no indications of stress dependence in the Raman spectra of the PMN layers.

Keywords:

• Superlattices
• ferroelectrics
• relaxors
• X-ray diffraction
• raman spectroscopy

PACS numbers:

• (1) 77.84.−s
• (2) 68.65.Cd
• (3) 78.30.−j
• (4) 78.80.−e