Determination of domain structure and abundance of epitaxial Pb(Zr, Ti)O₃ thin films grown on MgO(001) by rf magnetron sputtering

Abstract

Epitaxial Pb(Zr x Ti 12x )O 3 (x 0.0-0.32) ferroelectric thin films of 500 nm thickness were grown on MgO(001) single crystal substrates by in situ rf magnetron sputtering, and evolution of their domain structures is characterized by employing various x-ray diffraction techniques. X-ray u-2u scan showed the films were grown highly c-axis oriented with a tetragonal perovskite structure. 90 ± domain configuration was investigated using the x-ray rocking curve analysis for PZT 100 peaks in two different f angles. The rocking curve analysis showed that the degree of c-axis orientation and the crystalline quality of the films were improved continuously with increasing Zr concentration. The c-domain abundance as a function of Zr concentration was quantified using the x-ray rocking curves of PZT 001 and 100, taking account of structural factors and Lorentz-polarization factors. High temperature x-ray technique was also employed to quantify the domain structure as a function of temperature during cooling after reheating the samples to 650 ± C. During the cooling process, c-domain abundance was found to increase continuously while the crystalline quality of the films was deteriorated below the Curie temperature. The results led us to conclude that the transformation strain of the film at and below the Curie temperature plays a significant role in the final domain structure and abundance of epitaxial PZT thin films.132

Strain on ferroelectric thin films

“…There are only a few experimental determinations of the evolution of the misfit-strain with temperature [75,[97][98][99] whereas several evolutions of the complete set of lattice parameters evolution with temperature have been reported on Pb(Zr 1-x ,Ti x )O 3 thin films (e.g., see [100,101] for monodomain films and [79,82,83,102] for polydomain ones).…”

Epitaxial Stress‐Free Growth of High Crystallinity Ferroelectric PbZr0.52Ti0.48O3 on GaN/AlGaN/Si(111) Substrate

“…As a matter of comparison, the FWHM of our epitaxial PZT films is also much lower than previous reported values for PZT films on GaN and PZT on a YSZ buffered Si wafer . Further improvement of the crystalline quality of the PZT is limited by the lattice mismatch between MgO and PZT . This emphasizes the pivotal role of the MgO buffer layer in epitaxial growth of PZT films.…”

Domain structure sequence in ferroelectric Pb(Zr0.2Ti0.8)O3 thin film on MgO

“…13͒ and the domain structure was found to be 100% c domains. A polydomain structure has been reported by Lee et al, 14 with a decrease of the volume fraction of c domains ͑␣ c ͒ with increasing Ti concentration from 90% for PZT 32/ 68 down to 75% for pure PbTiO 3 . PbTiO 3 , the end member of PZT, has been studied as a thin film deposited on MgO by many authors.…”

“…Kim et al 23 reported T C film to be 10 K higher ͑40 K lower͒ than the bulk when heating ͑cooling͒. Temperature evolution of Pb͑Zr 1−x Ti x ͒O 3 ͑x = 1 , 0.92, 0.84, 0.76, 0.68͒ thin films deposited on MgO was reported by Lee et al 14 The out-of-plane lattice parameters as well as T C film were equal to the corresponding bulk values, i.e., the films considered were strain-free.…”