Surface Investigation of Ni₈₁Fe₁₉ Thin Film: Using ARXPS for Thickness Estimation of Oxidation Layers

Round 1

Reviewer 1 Report

Authors of reviewed manuscript investigated the surface of Ni₈₁Fe₁₉ thin film for thickness estimation of oxidation layers. This topic is relevant and worthy of study. However, the manuscript has many drawbacks.

1. It is not clear what the goal of such research, because that authors performed the surface analysis only for sample with a thickness of 100 nm. The dependence on other parameters, such as the grow rate, temperature, films thickness and others, on the thickness and chemical composition of oxides in films were not investigated.
2. It is not clear why such a narrow range of thicknesses was chosen (from 90 to 120 nm).
3. The AFM images presented in the Fig. 1 provide very little information because they are very similar. I think it is enough to show one image and the parameters of the other films (roughness) can be put in the table.
4. In my opinion, the information presented in Figures 5 and 8 is also superfluous. It would be enough to show the AEXPS spectra at two extreme take-off angles to show the dynamics of the change in oxides over the depth in the film.
5. Authors do not explain why the coercive field of film with thickness 120 nm increase so much compared to a film with a thickness of 110 nm (from ~3 Oe to ~13 Oe). The explanation by the authors that this is caused by a significant increase in the surface roughness “dramatic increase of H_c observed in Fig. 3b can be attributed to the high roughness of 120 nm thick sample”, is not convincing since the roughness increased only from 1.45 nm (for film of 110 nm thickness) to 1.67 nm (for film with thickness 120 nm). It should be noted that the roughness of the 110 nm film increases by the same value (~0.2 nm) as compared to the 100 nm film. In this case, no significant increase in the coercive field is observed.
6. In addition, the data in Fig. 3a and b are questionable. It is not clear how many measurements were made and how many samples with the same thickness were examined. It seems authors tested only one sample.
7. In addition, the citation of the reference [14] is incorrect: „FM/AF multilayer structure can easily be affected by the change in thickness of each single layer, as well as the surface morphology. Especially, when the thickness of individual layers falls below the critical thickness, the states and properties of surface and interface will dominate the magnetic properties [14]“. In this manuscript, there is no such data.

Author Response

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Reviewer 2 Report

Lines 79-81, The angles to measured are used in some methodology? Why these angles and not other ones?  It is necessary to write the importance of the XPS calibration.

Lines 84-89, It is necessary to clarify what are the positive correlation values between average grain size and  surface roughness. Why these values are important? You must be more specific about the reasons because the sample of 100 nm is the best.

Lines 96-99 Whats the meaning higher coercivity? What are the low and high values for NeFi? It is necessary to add references, discussion and importance for this research.

Lines 105-107 what are the defects kind (vacancies, interstitials, etc.)? It is necessary add references about coercivity vs.  roughness, if they exist.

Line 127 What are the angles that not indeterminate the equation?, e.g. zero angle to different heights.

Line 137 Besides to cite references is necessary to add kinetic energy values of the Ni photoelectron and its oxides.

I suggesting that the mathematical aproximation (line 141) is colocated as a part of equation 4.

what is the sense to include the figure 2b if the analysis of this one is not done?

It would be good to do a picture to understand the multilayers concept…

Correcting the title of the figure 3 “x” axis

In the conclusions (line 203) is said “also provides a minimum thickness for the pinning thickness of multilayers” what is the minimum thickness in NiFe oxide multilayers? How is demonstrated since technological point of view and scientific?

 

 

 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

In the legend of Fig. 1 it should be deleted the word “different”.