Longitudinal Magneto-Optical Kerr Effect of Nanoporous CoFeB and W/CoFeB/W Thin Films

Round 1

Reviewer 1 Report

I have studied the manuscript by Weiwei Zhang and coauthors and I can recommend it for publication in its present form.

Just a few comments that the authors might want to consider

1) Since you study CoFeB and W CoFeB W , and learn from the comparison you might want to add CoFeB to the title

2) The choice of the 40/40 Fe Co ratio is due to high Ms, low magnestostriction.....¿? 

3) when discussing null points and agreements and disagreements have you considered that you have an array not perfect, with well defined next neighbor distances but with no good long order?

4) related to 3. Have yo measured at a different incident angle, say 70º, and checked if the observed dependencies are the same?

 

5) I see some loops up to 300 Oem and some up to 900 Oe, Why? As the authors know "coercivity" depends on the maximum applied field, and the "coercive field" is when magnetic saturation is reached, and is more or less independent from the field magnitude beyond this point, 

6) Tungsten is a non ferromagnetic metal. Not a kind of non ferromagnetic metal.  I also see some statements claiming different "intrinsic" magnetization at different thicknesses of the FeCob film, please explain/clarify, I doubt you can see finite size effects in the Ms values at this thickness range

 

Author Response

Dear Editor and Referees,

We thank you for your constructive suggestions and comments. Based on your recommendations, we have revised our manuscript (Manuscript ID: coatings-1527520). Below are the point-by-point responses to each of the reviewers’ comments.

Response to reviewer 1

I have studied the manuscript by Weiwei Zhang and coauthors and I can recommend it for publication in its present form. Just a few comments that the authors might want to consider

1) Since you study CoFeB and W /CoFeB /W, and learn from the comparison you might want to add CoFeB to the title.

Response: Thank you for your helpful suggestion. “CoFeB” has been added to the title (The portion of the title in red on page 1).

2) The choice of the 40/40 Fe Co ratio is due to high Ms, low magnetostriction ?

Response:Yes. There are also the following reasons. The Co₆₀Fe₂₀B₂₀ thin film exhibited a higher degree of crystallization than the Co₄₀Fe₄₀B₂₀ thin film did. Amorphous magnetic materials or nanocrystalline materials of ultra-small grain size (here the sputtered Co40Fe40B20 film is usually amorphour or having crystalline size less than 3nm after annealing ) have some incomparable characteristics of highly crystalline magnetic materials, such as no grain boundary or ultra-small grain size, no or less structural anisotropy, and some parameters related to magnetism that can be changed in a large range. Therefore, there are not only excellent soft magnetic alloys with high permeability but also magneto-optical materials with good performance in amorphous magnetic materials. In addition, the amorphous alloy or nanostructural film with ultra-small grain size also has high resistivity, strong corrosion resistance, good toughness, mechanical tensile strength, and other excellent characteristics.

3) when discussing null points and agreements and disagreements have you considered that you have an array not perfect, with well-defined next neighbor distances but with no good long order?

Response: The anodic aluminum oxide template in our manuscript was fabricated using a two-step anodic oxidation method, which only has an ordered array in a short-range. However, in our manuscript, we do not involve the surface plasmon resonance mode so there is no need to make strict periodicity requirements for the template, just the effective refractive index based on the effective medium theory in general.

4) Related to 3. Have you measured at a different incident angle, say 70º, and check if the observed dependencies are the same?

Response: For the convenient investigation of the sensor’s application, the incident angle of 45 degrees in our manuscript was chosen to examine the detected performance, which is easy to operate. Therefore, we only measured the magneto-optical Kerr effect at an incident angle of 45 degrees. We did not measure the signal at a angle of 70^o. It is a good suggestion. We will do the angle-resolved measurement next.

5) I see some loops up to 300 Oe and some up to 900 Oe, Why? As the authors know "coercivity" depends on the maximum applied field, and the "coercive field" is when magnetic saturation is reached and is more or less independent from the field magnitude beyond this point.

Response: This is because the magnetization of some samples is already saturated and their coercivity is low. If we make the range uniform, the coercivity will not be obvious in figures, just for easy comparison in the text. The field range of the measurement is usually from -2000Oe to +2000Oe. Usually, we did measurement more than once for each sample. Therefore, we may optimize our measurement condition.

6) Tungsten is a non ferromagnetic metal. Not a kind of nonferromagnetic metal.  I also see some statements claiming different "intrinsic" magnetization at different thicknesses of the FeCob film, please explain/clarify, I doubt you can see finite-size effects in the Ms values at this thickness range.

Response: When the magnetic film and the nonferromagnetic metal (such as W, Pt, and Ta) with high spin-orbit effect are very thin, the spin-orbit effect and the finite-size effect can effectively affect the magnetization at the interface. However, in our manuscript, the thickness of the CoFeB film has reached up to above 100 nm, therefore, the finite-size effect in the Ms values is very low.

Yours,

Sincerely,

Yujun Song

University of Science and Technology Beijing

30 Xueyuan Road, Beijing 100083, China

Reviewer 2 Report

on paper “ Longitudinal Magneto-optical Kerr Effect of Nanoporous W/CoFeB/W Thin Films “ (coatings-1527520) by authors Weiwei Zhang, Zhanghua Chen, Vladimir I. Belotelov, Yujun Song submitted to Coatings

 

This is interesting paper. It reports the preparation and investigation of the structure and magneto-ptical properties of the nanoporous Co₄₀Fe₄₀B₂₀ and sandwich tungsten W/CoFeB/W thin films fabricated via anodic aluminum oxide template assisted magneto sputtering process. Introduction of non-ferromagnetic W layers can experimentally regulate the Kerr null points of the ferromagnetic thin films. Moreover, construction of W/CoFeB/W sandwich thin films can greatly increase the highest magneto-optical susceptibility and the saturated Kerr rotation angle by comparing with the CoFeB thin film of the same thickness. The presented experimental data are reliable and not cause much doubt. However, paper needs some improvements only after implementation of which it can be published:

1. I agree with the authors that different compounds are used as magnetic materials: “It has been demonstrated all-optical magnetization reversal in a 20 nm thick Ni film using a circularly- polarized light, giving the reversal speed to be 260fs, much faster than that in the other devices, such as MTJs and GMR junctions. 20”. All of them have both their advantages and their disadvantages. I understand the choice of object of study. This is the metal alloys and composites which have excellent magneto-optical properties. However, the alloys compounds are not free from some disadvantages. One of which is their low resistance to the aggressive influence of environmental factors such as temperature, oxygen and electromagnetic radiation. Oxide compounds in this sense are much more stable when used up to 1000 ºC. Moreover, there is such class of complex iron oxide compounds with excellent magnetic properties:

(1). D.A. Vinnik, A.Yu. Starikov, V.E. Zhivulin, K.A. Astapovich, V.A. Turchenko, T.I. Zubar, S.V. Trukhanov, J. Kohout, T. Kmječ, O. Yakovenko, L. Matzui, A.S.B. Sombra, D. Zhou, R.B. Jotania, C. Singh, Y. Yang, A.V. Trukhanov, Changes in structure, magnetizatin and resistivity of BaFe_12-xTi_xO₁₉, ACS Appl. Electron. Mater. 3 (2021) 1583-1593. https://dx.doi.org/10.1021/acsaelm.0c01081.

(2). M.V. Zdorovets, A.L. Kozlovskiy, D.I. Shlimas, D.B. Borgekov, Phase transformations in FeCo – Fe₂CoO₄/Co₃O₄-spinel nanostructures as a result of thermal annealing and their practical application, J. Mater. Sci.: Mater. Electron. 32 (2021) 16694-16705. https://doi.org/10.1007/s10854-021-06226-5.

This information should be noted in 1. Introduction.

2. Various methods for obtaining metallic alloys samples are known:

(3). D.I. Tishkevich, S.S. Grabchikov, S.B. Lastovskii, S.V. Trukhanov, T.I. Zubar, D.S. Vasin, A.V. Trukhanov, Correlation of the synthesis conditions and microstructure for Bi-based electron shields production, J. Alloys Compd. 749 (2018) 1036-1042. https://doi.org/10.1016/j.jallcom.2018.03.288.

(4). T.I. Zubar, V.M. Fedosyuk, S.V. Trukhanov, D.I. Tishkevich, D. Michels, D. Lyakhov, A.V. Trukhanov, Method of surface energy investigation by lateral AFM: Application to control growth mechanism of nanostructured NiFe films, Sci. Rep. 10 (2020) 14411. https://doi.org/10.1038/s41598-020-71416-w.

In 1. Introduction and 2. Experimental Section it is necessary to mention this information.

3. What is the oxygen stoichiometry of prepared composite samples? It is well known that the complex 3d-metal oxides easily allow the oxygen excess and/or deficit:

(5). S.V. Trukhanov, I.O. Troyanchuk, N.V. Pushkarev, H. Szymczak, Magnetic properties of anion-deficient La_1−xBa_xMnO_3−x/2 (0≤x≤0.30) manganites, J. Exp. Theor. Phys. 96 (2003) 110-117. https://doi.org/10.1134/1.1545390.

(6). A. Kozlovskiy, K. Egizbek, M.V. Zdorovets, M. Ibragimova, A. Shumskaya, A.A. Rogachev, Z.V. Ignatovich, K. Kadyrzhanov, Evaluation of the efficiency of detection and capture of manganese in aqueous solutions of FeCeO_x nanocomposites doped with Nb₂O₅, Sensors 20 (2020) 4851. https://doi.org/10.3390/s20174851.

Oxygen excess and deficit can increase and decrease the oxidation degree of transition metal cations. The changing of charge state of transition metal cations as a consequence of changing of oxygen content changes such electrical parameters as resistivity and band gap. An increase in the unit cell parameter may be also due to oxygen deficiency. This information should be also discussed in 3. Results and discussion.

4. The presented 6 papers should be inserted in References.

 

The paper should be sent to me for the second analysis after the moderate revisions.

Comments for author File: Comments.pdf

Author Response

Dear Editor and Referees,

We thank you for your constructive suggestions and comments. Based on your recommendations, we have revised our manuscript (Manuscript ID: coatings-1527520). Below are the point-by-point responses to each of the reviewers’ comments.

Response to reviewer 2

On paper “ Longitudinal Magneto-optical Kerr Effect of Nanoporous W/CoFeB/W Thin Films “ (coatings-1527520) by authors Weiwei Zhang, Zhanghua Chen, Vladimir I. Belotelov, Yujun Song submitted to Coatings. This is an interesting paper. It reports the preparation and investigation of the structure and magneto-optical properties of the nanoporous Co40Fe40B20 and sandwich tungsten W/CoFeB/W thin films fabricated via anodic aluminum oxide template-assisted magneto sputtering process. The introduction of non-ferromagnetic W layers can experimentally regulate the Kerr null points of the ferromagnetic thin films. Moreover, the construction of W/CoFeB/W sandwich thin films can greatly increase the highest magneto-optical susceptibility and the saturated Kerr rotation angle by comparing with the CoFeB thin film of the same thickness. The presented experimental data are reliable and do not cause much doubt. However, the paper needs some improvements only after implementation of which it can be published:

1. I agree with the authors that different compounds are used as magnetic materials: “It has been demonstrated all-optical magnetization reversal in a 20 nm thick Ni film using a circularly- polarized light, giving the reversal speed to be 260fs, much faster than that in the other devices, such as MTJs and GMR junctions. 20”. All of them have both their advantages and their disadvantages. I understand the choice of the object of study. There are metal alloys and composites which have excellent magneto-optical properties. However, the alloy compounds are not free from some disadvantages. One of which is their low resistance to the aggressive influence of environmental factors such as temperature, oxygen, and electromagnetic radiation. Oxide compounds in this sense are much more stable when used up to 1000 ºC. Moreover, there is such class of complex iron oxide compounds with excellent magnetic properties:

(1). D.A. Vinnik, A.Yu. Starikov, V.E. Zhivulin, K.A. Astapovich, V.A. Turchenko, T.I. Zubar, S.V. Trukhanov, J. Kohout, T. Kmječ, O. Yakovenko, L. Matzui, A.S.B. Sombra, D. Zhou, R.B. Jotania, C. Singh, Y. Yang, A.V. Trukhanov, Changes in structure, magnetization and resistivity of BaFe12-xTixO19, ACS Appl. Electron. Mater. 3 (2021) 1583-1593. https://dx.doi.org/10.1021/acsaelm.0c01081.

(2). M.V. Zdorovets, A.L. Kozlovskiy, D.I. Shlimas, D.B. Borgekov, Phase transformations in FeCo – Fe2CoO4/Co3O4-spinel nanostructures as a result of thermal annealing and their practical application, J. Mater. Sci.: Mater. Electron. 32 (2021) 16694-16705. https://doi.org/10.1007/s10854-021-06226-5.

This should be noted in 1. Introduction.

Response: Advantages and disadvantages of magnetic alloys have been noted in the introduction section. Additionally, a variety of complex iron oxide compounds with the excellent magnetic properties you mentioned have also been added to our manuscript in the introduction section (Sentences in red font on page 3 ).

2. Various methods for obtaining metallic alloys samples are known:

(3). D.I. Tishkevich, S.S. Grabchikov, S.B. Lastovskii, S.V. Trukhanov, T.I. Zubar, D.S. Vasin, A.V. Trukhanov, Correlation of the synthesis conditions and microstructure for Bi-based electron shields production, J. Alloys Compd. 749 (2018) 1036-1042. https://doi.org/10.1016/j.jallcom.2018.03.288.

(4). T.I. Zubar, V.M. Fedosyuk, S.V. Trukhanov, D.I. Tishkevich, D. Michels, D. Lyakhov, A.V. Trukhanov, Method of surface energy investigation by lateral AFM: Application to control growth mechanism of nanostructured NiFe films, Sci. Rep. 10 (2020) 14411. https://doi.org/10.1038/s41598-020-71416-w.

In 1. Introduction and 2. Experimental Section it is necessary to mention this information.

Response: The above-mentioned information has been added to the manuscript in the introduction section and experimental section (Sentences in red font on page 3).

3. What is the oxygen stoichiometry of prepared composite samples? It is well known that the complex 3d-metal oxides easily allow the oxygen excess and/or deficit:

(5). S.V. Trukhanov, I.O. Troyanchuk, N.V. Pushkarev, H. Szymczak, Magnetic properties of anion-deficient La1−xBaxMnO3−x/2 (0≤x≤0.30) manganites, J. Exp. Theor. Phys. 96 (2003) 110-117. https://doi.org/10.1134/1.1545390.

(6). A. Kozlovskiy, K. Egizbek, M.V. Zdorovets, M. Ibragimova, A. Shumskaya, A.A. Rogachev, Z.V. Ignatovich, K. Kadyrzhanov, Evaluation of the efficiency of detection and capture of manganese in aqueous solutions of FeCeOx nanocomposites doped with Nb2O5, Sensors 20 (2020) 4851. https://doi.org/10.3390/s20174851.

Oxygen excess and deficit can increase and decrease the oxidation degree of transition metal cations. The changing of the charge state of transition metal cations as a consequence of changing of oxygen content changes such electrical parameters as resistivity and bandgap. An increase in the unit cell parameter may be also due to oxygen deficiency. This information should be also discussed in 3. Results and discussion.

Response: During the fabrication process, the CoFeB target was used to form the CoFeB film on the substrate using the magnetron sputtering method at argon atmosphere. We did not use oxygen and try best to acoid the oxidization of the thin films.

4. The presented 6 papers should be inserted in References.

Response: The relevant papers you mentioned have been inserted in the References.

 

Yours,

Sincerely,

Yujun Song

University of Science and Technology Beijing

30 Xueyuan Road, Beijing 100083, China

 

 

Reviewer 3 Report

Submitted manuscript is devoted to the investigation of the longitudinal MOKE of CoFeB thin films deposited onto porous membranes. Although subject itself is interesting and widely discussed in the present day reports, the introduction (and discussion itself) are quite limited and narrow. The self-citation level when all authors are counted is above 25% and most important contributions of the other groups are not taken into account.

 

For example, MOKE studies description without referencing to the fundamentals is strange (A. Hubert and R. Schäfer, Magnetic Domains. Berlin, Germany: Springer, 1998). There is no referencing and comparative discussion with CoFeB thin films, which are the subject of special interest for many years (Garcia et al. Induced anisotropy, magnetic domain structure and magnetoimpedance e¤ect in CoFeB amorphous thin fims Journal of Magnetism and Magnetic Materials 191 (1999) 339-344; Hindmarch  et al. Origin of in-plane uniaxial magnetic anisotropy in CoFeB amorphous ferromagnetic thin films Phys. Rev. B 83, 212404 2011, etc.). Porous membranes with this kind of films are also well known (Ciureanu et al.  Magnetic properties of electrodeposited CoFeB thin films and nanowire arrays Electrochimica Acta 2005 50(22):4487-4497). There are leading groups in the world in this subject (at the University of Minnesota in USA, CSIC Materials Sci. Institution in Madrid and University of Oviedo in Spain) their contributions are also worth to be analyzed and taken into account for discussion.

 

Magnetic phase probes, including magnonic crystals , are also quite well described and different solutions for periodic structures and techniques are available – short multidisciplinary overview would be an advantage (Buznikov et al. Magnetoimpedance of Periodic Partly Profiled Multilayer Film Structures Physics of Metals and Metallography 2021, 122,755–760; Nikitov et al. Magnonics: a new research area in spintronics and spin wave electronics,” Phys.-Usp. 58, 1002–1028 (2015); Corrêa et al.Tailoring the magnetoimpedance effect of NiFe/Ag multilayer, J. Phys. D: Appl. Phys. 43, 295004–295007 (2010) and others).

 

The concept of magnetic biosensing is not really justified in the introduction and it must be also properly referenced (Baselt et al., A biosensor based on magnetoresistance technology. Biosens. Bioelectron. 1998, 13, 731–739.Brzeska et al. Detection and manipulation of biomolecules by magnetic carriers. J. Biotechnol. 2004, 112, 25–33. Chen et al. A prototype of giant magnetoimpedance-based biosensing system for targeted detection of gastric cancer cells. Biosens. Bioelectron. 2011, 26, 3246–3253; Yang et al. Giant magnetoimpedance based immunoassay for cardiac biomarker myoglobin. Anal. Methods 2017, 9, 3636–3642; Buznikov et al. Modelling of magnetoimpedance response of thin film sensitive element in the presence of ferrogel: Next step toward development of biosensor for in-tissue embedded magnetic nanoparticles detection. Biosens. Bioelectron. 2018, 117, 366–372, etc. ).

 

The aim of the work is absent at  the end of the Introduction, instead we read kind of diffused “strategy” description – this part must be carefully re-written.

 

The manuscript contains the electron microscopy images of the samples but it is well known that these kinds of materials tend to be clustering. Optical microscopy results would be important to evaluate the uniformity of them. For example, Figure 6 shows dependence of M(H) loops features as a function of the thickness of CoFeB part. The accuracy of thickness definition is not discussed in detail (51 ± 2? nm). How much this number varies over the length of 2-3 micrometers? In any case, the MOKE information depth in the CoFeB the alloys  (A. Hubert and R. Schäfer, Magnetic Domains. Berlin, Germany: Springer, 1998) is about 20 nm, means that analyzed information depth is the same for all cases here.

 

Metrological aspects are absent in the work – not a single graph shows the error bars (Fig. 8d must show them for sure).

 

The last part of the conclusions belongs to the discussion and future prospects, sensor applications are not proved for the designed material. This discussion, especially in a view for biosensors given in the Introduction, must be added.

At least one case of comparison with VSM would be an advantage.

Author Response

Dear Editor and Referees,

We thank you for your constructive suggestions and comments. Based on your recommendations, we have revised our manuscript (Manuscript ID: coatings-1527520). Below are the point-by-point responses to each of the reviewers’ comments.

Response to reviewer 3

1. Submitted manuscript is devoted to the investigation of the longitudinal MOKE of CoFeB thin films deposited onto porous membranes. Although subject itself is interesting and widely discussed in the present day reports, the introduction (and discussion itself) are quite limited and narrow. The self-citation level when all authors are counted is above 25% and most important contributions of the other groups are not taken into account. For example, MOKE studies description without referencing to the fundamentals is strange (A. Hubert and R. Schäfer, Magnetic Domains. Berlin, Germany: Springer, 1998). There is no referencing and comparative discussion with CoFeB thin films, which are the subject of special interest for many years (Garcia et al. Induced anisotropy, magnetic domain structure and magnetoimpedance e¤ect in CoFeB amorphous thin fims Journal of Magnetism and Magnetic Materials 191 (1999) 339-344; Hindmarch  et al. Origin of in-plane uniaxial magnetic anisotropy in CoFeB amorphous ferromagnetic thin films Phys. Rev. B 83, 212404 2011, etc.). Porous membranes with this kind of films are also well known (Ciureanu et al.  Magnetic properties of electrodeposited CoFeB thin films and nanowire arrays Electrochimica Acta 2005 50(22):4487-4497). There are leading groups in the world in this subject (at the University of Minnesota in USA, CSIC Materials Sci. Institution in Madrid and University of Oviedo in Spain) their contributions are also worth to be analyzed and taken into account for discussion.

 Response: A variety of references related to the MOKE, CoFeB have been added and more contributions of other leading groups are also discussed (Sentences in red font on page 3).

2. Magnetic phase probes, including magnonic crystals , are also quite well described and different solutions for periodic structures and techniques are available – short multidisciplinary overview would be an advantage (Buznikov et al. Magnetoimpedance of Periodic Partly Profiled Multilayer Film Structures Physics of Metals and Metallography 2021, 122,755–760; Nikitov et al. Magnonics: a new research area in spintronics and spin wave electronics,” Phys.-Usp. 58, 1002–1028 (2015); Corrêa et al.Tailoring the magnetoimpedance effect of NiFe/Ag multilayer, J. Phys. D: Appl. Phys. 43, 295004–295007 (2010) and others).

Response: Short multidisciplinary overview has been added to the manuscript (Sentences in red font on pages 1 and 2 )

3. The concept of magnetic biosensing is not really justified in the introduction and it must be also properly referenced (Baselt et al., A biosensor based on magnetoresistance technology. Biosens. Bioelectron. 1998, 13, 731–739.Brzeska et al. Detection and manipulation of biomolecules by magnetic carriers. J. Biotechnol. 2004, 112, 25–33. Chen et al. A prototype of giant magnetoimpedance-based biosensing system for targeted detection of gastric cancer cells. Biosens. Bioelectron. 2011, 26, 3246–3253; Yang et al. Giant magnetoimpedance based immunoassay for cardiac biomarker myoglobin. Anal. Methods 2017, 9, 3636–3642; Buznikov et al. Modelling of magnetoimpedance response of thin film sensitive element in the presence of ferrogel: Next step toward development of biosensor for in-tissue embedded magnetic nanoparticles detection. Biosens. Bioelectron. 2018, 117, 366–372, etc. ).

 Response: We have added this description of magnetic bioasensing in the revised text by citing these references. Thank you for this suggestion to emphasize the advantage of MOKE.

4. The aim of the work is absent at the end of the Introduction, instead we read kind of diffused “strategy” description – this part must be carefully re-written.

 Response: The work aims to provide a method for the regulation of magnetization reversal via the optimization of the microstructure of multilayered thin films. The end of the introduction has been rewritten (Sentences in red font on page 3).

5. The manuscript contains the electron microscopy images of the samples but it is well known that these kinds of materials tend to be clustering. Optical microscopy results would be important to evaluate the uniformity of them. For example, Figure 6 shows dependence of M(H) loops features as a function of the thickness of CoFeB part. The accuracy of thickness definition is not discussed in detail (51 ± 2? nm). How much this number varies over the length of 2-3 micrometers? In any case, the MOKE information depth in the CoFeB the alloys  (A. Hubert and R. Schäfer, Magnetic Domains. Berlin, Germany: Springer, 1998) is about 20 nm, means that analyzed information depth is the same for all cases here.

Response: it is typically difficult to confirm the film thickness on the AAO template. However, conventionally, researchers often deposit films on AAO and a smooth substrate (e.g., glass and wafer) with the same deposition time. The film thickness on the smooth substrate is then characterized using an optical ellipsometer or AFM method. In our experiment, we used this method to describe the mean film thickness on AAO. We have provided an adequate description regarding this in the article (Sentences in red font on page 7).

6. Metrological aspects are absent in the work – not a single graph shows the error bars (Fig. 8d must show them for sure).

Response： Fig. 8d is used just to summarize the result from Figs. 8a to 8c to see more clearly than the curves observed only from Figure 8a-8c, and metrological aspects are delayed now due to covid-19. We may do more times of measurement for the error bar after Covid-19 is controlled and allowed us to go out doing more experiment. Anyway, the trend is reliable.

7. The last part of the conclusions belongs to the discussion and future prospects, sensor applications are not proved for the designed material. This discussion, especially in a view for biosensors given in the Introduction, must be added. At least one case of comparison with VSM would be an advantage.

Response: The description of the thickness sensor has been marked (The portion of the title in red on page 15). For the biosensing application, we have added the description of the related reflectance and dielectric change or refractive indexfor the possible applications of our structure in biosensors at the end of conclusion of the new version.

 

Yours,

Sincerely,

Yujun Song

University of Science and Technology Beijing

30 Xueyuan Road, Beijing 100083, China

Reviewer 4 Report

Congratulations, solid and timely work.

Round 2

Reviewer 2 Report

Referee Report

on paper “ Longitudinal Magneto-optical Kerr Effect of Nanoporous W/CoFeB/W Thin Films “ (coatings-1527520-v2) by authors Weiwei Zhang, Zhanghua Chen, Vladimir I. Belotelov, Yujun Song submitted to Coatings

 

It is clearly seen that further efforts are required in order for the paper to be recommended for publication. The authors should pay more attention to the comments and additions of the reviewer in order to achieve the desired result promptly:

1. The authors should discuss in detail the stability of the chemical composition of the studied samples. What is the oxygen stoichiometry of prepared composite samples? It is well known that the complex 3d-metal oxides easily allow the oxygen excess and/or deficit:

(1). S.V. Trukhanov, I.O. Troyanchuk, N.V. Pushkarev, H. Szymczak, Magnetic properties of anion-deficient La_1−xBa_xMnO_3−x/2 (0≤x≤0.30) manganites, J. Exp. Theor. Phys. 96 (2003) 110-117. https://doi.org/10.1134/1.1545390.

(2). A. Kozlovskiy, K. Egizbek, M.V. Zdorovets, M. Ibragimova, A. Shumskaya, A.A. Rogachev, Z.V. Ignatovich, K. Kadyrzhanov, Evaluation of the efficiency of detection and capture of manganese in aqueous solutions of FeCeO_x nanocomposites doped with Nb₂O₅, Sensors 20 (2020) 4851. https://doi.org/10.3390/s20174851.

Oxygen excess and deficit can increase and decrease the oxidation degree of transition metal cations. The changing of charge state of transition metal cations as a consequence of changing of oxygen content changes such electrical parameters as resistivity and band gap. An increase in the unit cell parameter may be also due to oxygen deficiency. This information should be also discussed in 3. Results and discussion.

2. The Reference 41 shuld be corrected:

[41] T.I. Zubar, V.M. Fedosyuk, S.V. Trukhanov, D.I. Tishkevich, D. Michels, D. Lyakhov, A.V. Trukhanov, Method of surface energy investigation by lateral AFM: Application to control growth mechanism of nanostructured NiFe films, Sci. Rep. 10 (2020) 14411. https://doi.org/10.1038/s41598-020-71416-w.

3. The presented 2 papers should be inserted in References.

 

The paper should be sent to me for the third analysis after the minor revisions.

Comments for author File: Comments.doc

Reviewer 3 Report

Authors carefully revised the manuscript and it can be published in the present state.