Influence of Na/Mg Co-Doping in Tuning Microstructure, Transport, Optical, and Magnetic Properties of TiO2 Compounds for Spintronics Applications
Round 1
Reviewer 1 Report
The authors studied the structure, surface structure, transport (dielectric and Hall Effect), optical and magnetic properties of Ti0.94-yNa0.06MgyO2 (y=0-0.08) compounds synthesized by solid-state route method. The research content of the article is relatively rich and systematic, but the representation is lack of certain discussion. In general, the paper is of interest and it can be reconsidered after some revision.
1. The labels in Figure 1 and Figure 2 and the two Figures (and Figure 8) are very vague, which makes it impossible to see them clearly. Please modify these Figures.
2. The results of EDS should be provide in a Table [see Hui Zhang et al, J. Appl. Phys. 131, 043901 (2022); doi: 10.1063/5.0078188].
3. The discussions of relevant literature on microstructure, surface morphology, EDS, and magnetic properties could be further enhanced, which can link to the existing work. Authors should cite the following relevant recent work in the introduction and/or discussion part: Hui Zhang et al, J. Appl. Phys. 131, 043901 (2022);doi: 10.1063/5.0078188.
4. In Figure 13, from the M-H loop of Ti0.94-yNa0.06MgyO2 with y =0.08 compounds, HC cannot be observed. Partial enlarged view of M-H loop within low field area should be provided.
5. The value of coercivity of Ti0.94-yNa0.06MgyO2 with y = 0, 0.04, and 0.08 compounds should be described in the result and discussion part.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript by Narzary and Srivastava et al., discusses about effect of Na/Mg co-doping in TiO2 compounds for spintronic applications. Although the work is quite scientific, but the analysis and discussion is in nascent stage to judge its suitability for acceptance. The authors are required to revise the present manuscript thoroughly including the suggestions followed by before any final decision can be made.
1. The abstract doesn't include any significance of Na doping in TiO2 along with Mg doping. The authors should modify the abstract according to the title for better clarity of the content.
2. The authors stated that, "doping is a typical technique for modifying transition metals". They should explain what does this statement mean, does doping is a technique, does it only meant for metal not for material, how does this implied over here in enhancement of physio-chemical properties of TiO2 compounds.
3. Authors should specify recent advancements in spintronics using TiO2 materials in an introduction section.
4. Although the author has prepared Ti0.94-yNa0.06MgyO2 (y= 0, 0.02, 0.04,0.06 and 0.08). The characterizations made for different samples within series. It will be more better if they discuss all of them for the same sample to establish any relation in a proper fashion.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Review Report Manuscript ID: magnetochemistry-1976532
The present manuscript provides a detailed study on the structural, microscopic, dielectric, optical, electronic, and magnetic properties on the influence of Na or Mg co-doping in TiO2. The authors claim that the observed properties would be useful for the future development of spintronics and opto-electronics devices using these doped compounds. The present study is detailed, and the manuscript has been written in a clear and constructive manner. I recommend PUBLICATION of the manuscript subject to the following revisions:
<page 3, line 104>
The authors state that the XRD has been done on Ti0.94 Na0.06O2 compound and have reported the lattice parameters. However, in the subsequent sections (for instance, microstructure study by SEM), the authors state that the sample used in Ti0.90Na0.06Mg0.04O2, Ta0.86Na0.06Mg0.08O2. This becomes confusing for the readers to understand as they cannot understand how many samples were investigated. I would recommend the authors to make a table showing the compositions of the all the samples involved in this study or clearly state it in the manuscript.
<page 3, line 106>
The authors state that the crystallite size of the Ti0.94 Na0.06O2 compound is 60-80 nm (from XRD). Subsequently, the authors state that the particle size of Ti0.90Na0.06Mg0.04O2, Ta0.86Na0.06Mg0.08O2 is 20 to 70 micrometer (from SEM). Taking into account the prolonged annealing process carried out by the authors, why is there such a large difference between the sizes from these two measurements?
<page 3>
The texts (in red) inside the SEM figures are barely visible. Please change the color.
<page 4>
The texts (in red) inside the SEM figures are blurry and poorly visible. Furthermore, the x and y scale readings of the EDAX images are not visible at all. Please enhance the resolution of the images so that the reader can properly understand.
<page 5, line 140>
There will be a space in “compoundswere”.
<page 5, line 142>
The authors state “Most of the C1s peaks at 284.6 eV is a direct result of atmospheric pollution”. It is not clear to me what it means. Please clarify.
<page 11, line 281>
The authors state “….alternating current flowing through a material increases the pace at which charge carriers hop…”. Can the authors provide an estimate of how much the speed of the charge carriers enhances within their measured frequency range?
<page 12>
Figure 10: Why does the carrier density show a peak around 6%Mg concentration, as observed from Hall measurements. In other words, why does the carrier density decrease for higher Mg concentrations?
<page 16>
Figure 13: Can the authors provide a temperature dependent magnetization study to show the ferromagnetic nature. From Figure 13, it is understood that the remanence (magnetization at zero field) is small for Mg00, increases for Mg0.4 and then is again virtually zero for Mg08. Can the authors comment on this underlying reason responsible for this behavior.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The paper has been improved and can be accepted in current form.
Reviewer 2 Report
The manuscript has been modified substantially as per the suggestions. This can be accepted in its current format with minor corrections such as in the figure-1 containing FESEM images caption (b) has to be included inside the image.
