Nonlinear Optics for Crystallographic Analysis in Lead Zirconate Titanate
, Mikhail Vladimirovich Staritsyn 2, Igor Petrovich Pronin 3, Stanislav Viktorovich Senkevich 3 and Elena Dmitrievna Mishina 1
Round 1
Reviewer 1 Report
The authors did a comprehensive study on the azimuthal dependences of the optical second harmonic generation signal from PZT films to determine symmetry and orientation of crystallites. It is clearly stated and some interesting results are found. I think the manuscript could be accepted.
I do have some questions and suggestions：
1. p3, "with three crystallographic orientations". Is this film single crystalline?
2. In page 5, in sentences "...after some recalculation (eq. 3.1-3.6)."，and“a single formula (eq. 4) with 5 unknown variables”, the equations seem missing.
3. Crystallographic Analysis methods should give a more comprehensive review, such as recently developed full-angle PLM, other SHG works.
Author Response
Letter to reviewers
Questions are marked green.
Text form the paper is written in italic.
Questions of the first reviewer:
- p3, "with three crystallographic orientations". Is this film single crystalline?
The features of crystal structure is the main questions of this study. Although it is quite common that PZT films that are obtained by magnetron sputtering are polycrystalline.
- In page 5, in sentences "...after some recalculation (eq. 3.1-3.6)."，and “a single formula (eq. 4) with 5 unknown variables”, the equations seem missing.
Yes, we agree and have changed the text accordingly:
(191-194 rows)
These experimental dependencies were fitted by a single formula (eq. 11), which gives 13 nonlinear susceptibility tensor components and 6 weight coefficients for 6 phases. The fitting curves correspond quite well to the experimental azimuthal dependences of the SHG intensity (Figure 4).
- Crystallographic Analysis methods should give a more comprehensive review, such as recently developed full-angle PLM, other SHG works.
We put information of recent developments in linear PLM and SHG microscopy into introduction part, which was fully revised.
Reviewer 2 Report
Journal: Coatings
Manuscript ID.: coatings-2112187
Title: "Nonlinear optics for crystallographic analysis in lead zirconate
titanate"
Recommendation: The manuscript could be accepted for publication after some major modifications.
Reviewing report:
The results are new and interesting. The similarity (8 words) is only 9%. This is excellent. I would like to suggest that it can be published after the following comments have been fixed:
(1) The Materials and Methods Part needs to be in detail. Also, please write the equations that are used for more clarification.
(2) The explanation of the results is not clear enough. This section must be revised seriously.
(3) What happened when the lead zirconate titanate films (PZT) with zirconium/titanium were substrated on the platinized Glassceram (ST-50) and silicon (Si) substrates?
(4) What do you mean by dielectric polarization?
(5) Define the angle ?1 in equation (2.1).
(6) Please cite these references:
a- https://doi.org/10.1038/ncomms15768
b- https://doi.org/10.1063/1.2894595
c- https://doi.org/10.1016/j.jallcom.2015.08.177
(7) Conclusions should be improved.
(8) Please replace references 4 and 18 with other references above 2000.
Comments for author File: 
Comments.pdf
Author Response
Letter to reviewers
Questions are marked green.
Text form the paper is written in italic.
Questions of the second reviewer:
(1) The Materials and Methods Part needs to be in detail. Also, please write the equations that are used for more clarification.
In this section we add subsections. Corrected the sequence numbers of equations. Matrices names were corrected to avoid misunderstandings (Turn became Turn1 and Rot became Turn2).
(137-143 rows)
Eq. 11 is used for fitting the experimental data. The fitting parameters are the phase fractions Aj (5 parameters, taken into account that ∑Aj=1) and the tensor components normalized on of monoclinic phase (12 parameters). In the fitting procedure for each spherulite, 72 azimuthal dependences were considered for 72 different spots, in which nonlinear susceptibilities were kept the same for the whole spherulite, while the phase fractions were different fitting parameters for each spot of the shperulite. For the fitting procedure, the Wolfram research package was used.
(2) The explanation of the results is not clear enough. This section must be revised seriously.
Added:
(239-243 rows)
30 degree temperature difference between two samples can affect growth rate and filling factor (continuous film or separate islands) but it seems that it is not enough to significantly change phase сomposition. Orientation distribution slightly differ for each spherulite even on the same sample but there is no significant correlations due to temperature change.
(290-295 rows)
Comparison of SHG microscopy and EBSD reveals the following: On glassceram substrate orientation and symmetry distributions on spherulite were not symmetrical relative to the center (Figure 2 b,c) in contrast to those on silicon substrate (Figure 5). It can be clearly seen on pole figure (Figure 7c) that opposite regions on spherulite on glassceram that are located on other sides of diameter have different orientation. In this regard SHG PLM and XRD results prove each other.
(3) What happened when the lead zirconate titanate films (PZT) with zirconium/titanium were substrated on the platinized Glassceram (ST-50) and silicon (Si) substrates?
The question about two substrates was clarified in Sample section:
(68-72 rows)
The use of two types of substrates was determined by the difference in the nature of two-dimensional mechanical stresses acting on the film. In the case of glassceram, compression stress acted on the film, while in the case of silicon, tension stress acted on the film [24]. This allows to investigate influence of such stresses and is common topic of research [25].
(4) What do you mean by dielectric polarization?
The definition is added:
(98-99 rows)
that is, the dipole moment per unit volume
(5) Define the angle ?1 in equation (2.1).
Angle θ1 in equation is replaced by θ with following definition:
θ=0 is the angle of incidence
(6) Please cite these references:
a- https://doi.org/10.1038/ncomms15768
b- https://doi.org/10.1063/1.2894595
c- https://doi.org/10.1016/j.jallcom.2015.08.177
We added these references as ## 15,16 and 25.
(7) Conclusions should be improved.
We completely revised conclusions
(301-314 rows)
Our research shows the capabilities of SHG microscopy to study the local crystallographic structure of PZT ferroelectric films and obtain the maps of the fraction of different syngonies and crystallographic phases. Our method is based on the measurements followed by fitting of full-angle azimuthal (polarization) dependences of SHG intensity for each chosen spot of the film. In spite of big number of fitting parameters, they can be resolved due several operations. Firstly, the fitting parameters are separated in two groups: the first group consists of parameters, which are equal for all spots measured (nonlinear susceptibility tensor components), while the second group consists of the parameters which are unique for each spot measured (fractions of crystallites of different orientations and syngonies). We show that SHG microscopy allows to distinguish between different syngonies which are even close to the cubic one. In the same time EBSD method is not capable for that.
Based on the presented techniques, we can conclude that the main features of growth of PZT thin films are nearly uniform mixture of tetragonal and monoclinic phases, which composition corresponds to morphotropic phase boundary. Tensile or compressive stresses acting on PZT films from the side of silicon or glassceram substrates do not practically influence on phase mixture.
The substrate affects orientation distribution, which was proven both by SHG microscopy and EBSD. A slight non-uniform distribution of orientations, especially of tetragonal phase, correlates with radial misorientation in perovskite spherulites.
(8) Please replace references 4 and 18 with other references above 2000.
Citation 4 was replaced by
Oikawa, T., Aratani, M., Funukubo, H., Saito, K., Mizuhira, M. Composition and orientation dependence of electrical properties of epitaxial Pb(Zr1-xTix)O3 thin films grown using metalorganic chemical vapor deposition, J. Appl. Phys. 2004, 95(6), 3111-3115. https://doi.org/10.1063/1.1645646
Citation 18, which became 26 in the new version, is the pioneer work regarding SHG and polarization in ferroelectrics. Sometimes it is forgotten by researches. We believe it is important to remember the origins.
Round 2
Reviewer 2 Report
In this revised manuscript, all the points and questions raised previously are answered, necessary corrections are done. The paper can be published in the present form.
