Effect of Antimony Content on Transition Behavior and Electric Properties of (K_0.44Na_0.52Li_0.04)(Nb_0.9−xTa_0.10Sb_x)O₃ Ceramics

Round 1

Reviewer 1 Report

 

The paper is very interesting however it presents some lacks which should be improved:

Line 72: The Authors wrote: abbreviated as (K0.44Na0.52Li0.04)Nb0.9-xTa0.1SbxO3 “ – this is not the abbreviation

Line 85-86: There are two various sentences with the same meaning: Peak locations were fitted based on the form of a Lorentz peak. Peaks positions were fitted assuming a Lorentz peak shape

Figure 3: The number of decimal digits in the case of Fig.3a is devoided of physical sense. Give no more than two decimal digits in uncertainty. I suggest adding a horizontal scale in Figures 3a and 3b

Why only 0.02 and 0.04 contents of Sb were investigated?

In what range of temperatures were dielectric properties investigated?

The presentation of TO-T is not persuasive enough - they are practically invisible

 

 

Author Response

Answers to reviewers

The Comments by the Reviewers are highlighted in italic, whereas the response and the revision of the revised manuscript are given in BLUE.

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We would like to acknowledge the reviewers for their positive evaluation and for the comments they have made for improving our work. Please find our answers to the reviewers’ comments below.

Reviewer 1

The paper is very interesting however it presents some lacks which should be improved:

Response: We really appreciate the positive point of view that the referee has about the manuscript.

1. Line 72: The Authors wrote: abbreviated as (K0.44Na0.52Li0.04)Nb0.9-xTa0.1SbxO3 “ – this is not the abbreviation

Response: Thank you for your comments. We have corrected this typographical error.

2. Line 85-86: There are two various sentences with the same meaning: Peak locations were fitted based on the form of a Lorentz peak. Peaks positions were fitted assuming a Lorentz peak shape

Response: Thank you for your comments. We have attended those mistakes.

3. Figure 3: The number of decimal digits in the case of Fig.3a is devoided of physical sense. Give no more than two decimal digits in uncertainty. I suggest adding a horizontal scale in Figures 3a and 3b

Response: We are thankful to the reviewer for this suggestion. Figure 3a-b has been modified following the reviewer’s suggestion.

4. Why only 0.02 and 0.04 contents of Sb were investigated?

Response:  In order to clarify this point, a sentence has been included in the Introduction Section of the revised version of the manuscript (see page 2, lines 65-69).

Sb concentration used in this work was chosen based on Saito composition and Rubio et al. studies [9, 21-22], who observed that 0.04 mol % of Sb showed the best properties. Here, we want to elucidate if it is possible to reduce the Sb concentration in these KNL-NTS piezoceramics.

 

5. In what range of temperatures were dielectric properties investigated?

Response: More information about the temperature range used in dielectric properties investigated has been included in the revised version of the manuscript (Experimental section, page 3, lines 109-111).

The dielectric characteristics were evaluated at different temperatures between 25 ºC and 500 ºC and in the frequency range 100 Hz to 1 MHz using the HP4284A equipment.

 

6. The presentation of TO-T is not persuasive enough - they are practically invisible

Response: Thank you for your comments. As it is observed in Figure 5a, the T_O-T drastically decreases with the Sb⁺⁵ content evidencing that this phase transition is clearly sensitive to the Sb⁺⁵ content. However, this O-T phase transition is not enough clear because it is below or close to room temperature, depending on the x content. Considering that the T_o-T values are not persuasive enough for the compositions x=0.02 and x=0.04, we have decided to remove Figure 5c and modify the explanation for clarity. (see page 7, lines 232-337 and the new Figure 5)

Reviewer 2 Report

This manuscript presents the synthesis and electrical properties of (K0.44Na0.52Li0.04)(Nb0.9-xTa0.10Sbx)O3 ceramics. The sample is well characterized, and the data is explained well. As a whole, the topic is interesting and is suitable for publication in Materials. I have the following comments, which may be considered before accepting the manuscript for publication. 

 

1.     The author can add to the introduction several examples of other perovskite structured compounds that can show electrical, magnetic, and optical properties and potentially interest more readers. Some related works may be cited, DOI: 10.1021/acs.inorgchem.1c03624 ; https://doi.org/10.3390/app8010062 ; https://doi.org/10.1016/j.nanoen.2016.02.036 ; etc.

 

2.     The author discusses changes in the crystal structure (as decreased lattice parameter) due to differences in ionic radii. I suggest presenting a refinement to evaluate the structural parameters of these compounds. At least it reports what group of spaces this compound adopts. Is it possible to observe a shift of the XRD peak with a change in the composition of x?

 

3.     On page 5, line 151, the author states that the Raman shift to a higher frequency due to structural distortion leads to a more tetragonal symmetry. I argue that a more distorted structure results in a higher symmetry that is orthorhombic. What does the author think about this?

 

4.     The author analyzed sample composition with EDS. Is the author sure about these compositional results, while usually, the O content in the sample is difficult to be accurate? The author can estimate the nominal formula of the compound obtained from the EDS results.

 

5.     I doubt the results of the transition temperature analysis shown in Fig. 5. It can be seen from Fig 5a. that the Tc temperature for x=0 is around 400 °C, then decreases for x=0.02 around 300 °C, and is observed to increase for x=0.04 around 350 °C. However, in Fig 5b, which shows the value of Tc, this value decreases with increasing composition. Which data is correct?

 

6.     The author mentions that this increase in ferroelectric properties is related to many factors, such as grain size, dielectric permittivity, etc. The following statement requires a reference as support: Doi: 10.1016/j.ceramint.2020.03.007, etc.

7.     I suggest the author list all values of electrical properties in a Table; it is easier to compare the ferroelectric value with the dielectric constant at room temperature or Tc.

Author Response

Answers to reviewers

The Comments by the Reviewers are highlighted in italic, whereas the response and the revision of the revised manuscript are given in BLUE.

----------------------------------------------------------------------------------------

We would like to acknowledge the reviewers for their positive evaluation and for the comments they have made for improving our work. Please find our answers to the reviewers’ comments below.

Reviewer 2

This manuscript presents the synthesis and electrical properties of (K0.44Na0.52Li0.04)(Nb0.9-xTa0.10Sbx)O3 ceramics. The sample is well characterized, and the data is explained well. As a whole, the topic is interesting and is suitable for publication in Materials. I have the following comments, which may be considered before accepting the manuscript for publication. 

Response: We really appreciate the positive point of view that the referee has about the manuscript.

1. The author can add to the introduction several examples of other perovskite structured compounds that can show electrical, magnetic, and optical properties and potentially interest more readers. Some related works may be cited, DOI: 10.1021/acs.inorgchem.1c03624 ; https://doi.org/10.3390/app8010062 ; https://doi.org/10.1016/j.nanoen.2016.02.036 ; etc.

Response: Thank you for your comments. The references suggested by the reviewer have been incorporated in the introduction section as references 10, 11 and 15.

 

2. The author discusses changes in the crystal structure (as decreased lattice parameter) due to differences in ionic radii. I suggest presenting a refinement to evaluate the structural parameters of these compounds. At least it reports what group of spaces this compound adopts. Is it possible to observe a shift of the XRD peak with a change in the composition of x?

Response: Thank you for your comments. Unfortunately, our XRD equipment cannot filter K-a radiation, making very difficult to do a correct refinement. 

We have introduced explanatory text addressing the question asked by the reviewer (see page 4, lines 137-142):

However, different effects are produced with the Sb⁵⁺ addition. On the one hand, the substitutional addition of Sb⁵⁺ should reduce the cell (due to the smaller ionic radius) displacing the peaks towards higher angles, but on the other hand, the increasing concentration of Sb⁵⁺ generates a structural change modifying the T/O content in the structure. Unfortunately, through our XRD it is not possible to filter the influence of Kα₂ radiation and consequently the precise adjustment by the Rietveld method cannot be carried out.

 

3. On page 5, line 151, the author states that the Raman shift to a higher frequency due to structural distortion leads to a more tetragonal symmetry. I argue that a more distorted structure results in a higher symmetry that is orthorhombic. What does the author think about this?

Response: We acknowledge the comment of the referee and appreciate the opportunity to clarify this point. As the referee suggests, usually the orthorhombic symmetry presents a more distorted structure than tetragonal symmetry. Thus, a higher A_1g Raman shift is expected in the O region, but A_1g achieves lowest values in KNL-NTS. The abrupt decrease in the A_1g value in the O region may be understood here as a consequence of the domain-wall freezing effect. ^{[X. L. Zhang, Z. X. Chen, L. E. Cross, and W. A. Schulze, J. Mater. Sci. 18, 968 (1983) and Ochoa, D.A., Esteves, G., Jones, J.L., Rubio-Marcos, F., Fernández, J.F., García, J.E. Extrinsic response enhancement at the polymorphic phase boundary in piezoelectric materials. (2016) Applied Physics Letters, 108 (14), art. no. 142901]}

 

4. The author analyzed sample composition with EDS. Is the author sure about these compositional results, while usually, the O content in the sample is difficult to be accurate? The author can estimate the nominal formula of the compound obtained from the EDS results.

Response: Thank you for your comments. The nominal formula of the compound obtained from the EDS results were estimated and incorporated in the manuscript and the O content was checked. (see page 6 lines 200-210 and new Figure 4).

 

5. I doubt the results of the transition temperature analysis shown in Fig. 5. It can be seen from Fig 5a. that the Tc temperature for x=0 is around 400 °C, then decreases for x=0.02 around 300 °C, and is observed to increase for x=0.04 around 350 °C. However, in Fig 5b, which shows the value of Tc, this value decreases with increasing composition. Which data is correct?

Response: We really appreciate that the referee alerts about this inconsistency. In fact, we have detected that Figure 5 had a mistake, the ε'-T curve corresponding to the composition x=0.04 had been changed by the ε'-T curve of the composition x=0.02. Therefore, we have corrected the inconsistency in the revised version of the manuscript. (see page 7, lines 232-337 and the new Figure 5).

6. The author mentions that this increase in ferroelectric properties is related to many factors, such as grain size, dielectric permittivity, etc. The following statement requires a reference as support: Doi: 10.1016/j.ceramint.2020.03.007, etc.

Response: Thank you for your comments. The reference was incorporated in the corresponding section as 29.

 

7. I suggest the author list all values of electrical properties in a Table; it is easier to compare the ferroelectric value with the dielectric constant at room temperature or Tc.

Response: Table I was modified, including the suggestions proposed by the reviewe

 

Round 2

Reviewer 2 Report

I am happy that the authors have revised their manuscript in line with all reviewer comments and it is now suitable for publication.