Review Reports

Round 1

Reviewer 1 Report

The current work focuses on phase composition and magnetic properties of nanoparticles with magnetite-maghemite structure. The author’s some effort into the manuscript, but major issues should be addressed. 

 

Abstract

- Preparation of nanopowders with mixed magnetite-maghemite composition has been intensively studied. So, rephrase the abstract with the novelty of this work and the main output.

-Line 14, insert abbreviation (EPR) 

-Line 17, correct typo, Fe3+ and Fe2+

- Line 16-18, rephrase this sentence to be clear to the reader

 

Keywords 

- nanopowder in keyword should be inserted

 

Introduction

-The introduction does not provide sufficient background and all relevant references are not included.

-The novelty of this work is not highlighted and the author's contribution was unclear compared to other previous works. 

-Line 44, how to phase identification between magnetite nanoparticles and maghemite by FTIR!!! More details are required to clear this point.

 

Materials and Methods

-A list of used materials with their purity should be inserted.

-More details are required in the experimental section: 

The amount of used materials in mole beside weight (g) should be inserted for easier reproduction by the reader.

Amount of NH4OH solution used?

Ar bubbling rate?

Ultrasonication? Bath or electrode? Power?

 

 

Results and discussion 

-One of the main problems in the manuscript is that the authors show only results without interpretations of details of it or confirmation by citation. More details are required to explain the obtained results. 

- More details on XRD discussion should be inserted, 

- Where VSM and magnetic properties of the prepared samples?

-Line 115, superparamagnetics!! No evidence supports this claim. More details are required to support this claim

- FIG 1, high-quality appearance and resolution are required?, what is magnification?

 

Conclusions

Rephrase this section to be clearer to the reader and avoid repetition from the abstract section

 

References

Delete Line 272-281 

 

Extensive editing of English language required

Author Response

Please, see attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript “Phase composition and magnetic properties of nanoparticles 2 with magnetite-maghemite structure” describes the precipitation synthesis of iron oxide nanoparticles and their characterization by the EPR technique. I recommend publishing it after major revision concerning the following points:

1. Synthesis – the synthesis of maghemite samples is described in an unclear way. 

- First: from the description it appears that the authors use a mixture of FeCl2 and FeCl3 for it. Why not use only FeCl3, where the expected oxidation state of iron in maghemite is only 3+? 

- Second: The ultrasonication is applied only for maghemite samples. What is the reason for this action? Why ultrasonication is not used for both samples? Please provide the considerations for such synthesis and enhance this part of the manuscript.

 

2. How the average particle size is determined? Was it the mean coherent domain size from the XRD line broadening (one or multiple peaks?) or it is evaluated from the TEM photographs?

3. Why (111) peak is missing from the XRD patterns? Please, provide the enhanced XRD patterns.

4. The unit cell parameters of the two phases differ by very little and their values are closer to that of the maghemite than to that of magnetite. What are the reasons for this? In fact, both samples seem to be an intermediate between maghemite and magnetite. Please comment.

5. What measurements were performed to obtain the data in Table 2? Such measurements were not described in the Experimental part. The corresponding Figures were not presented. Table 2 title is missing. Discussion is missing. It looks as if a part of the work is missing.

Author Response

Please, see attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

all issues are solved and the manuscript is accepted in the present form.

 Moderate editing of English language required

Reviewer 2 Report

The author's replies to my suggestions are reasonable and the revised version of the manuscript can be accepted for publication.