Magnetron-Deposited FeTiB Films: From Structural Metastability to the Specific Magnetic State
, Eugene V. Harin 1, Philipp V. Kiryukhantsev-Korneev 2,*, Olga M. Zhigalina 3,4 and Galina Sh. Usmanova 1
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
A very good and balanced article. The experimental data and their evaluation are logical and comprehensible.
There are some minor comments that should be revised.
1. when one speaks of Rietveld analysis, there is a program behind it, which one?
2. for the structural data there is the PDF file of the ICDD or the freely available COD database. Therefore, this data should also be used for the evaluations and deviations should be shown. The crystal structure can also be created from the str or cif files for high-quality publications and should also be shown for better illustration. The crystal structure can then also be used to better explain the layer structures that often form in the elementary cells for the magnetic properties.
3. Equation (2) is new to me, the Russian source is not available to me. This should be backed up with another source, because the results found here take up a lot of space and are very significant. The R-values determined can then be compared with the lists from the PDF or COD files.
4. figure 1 could be drawn a little wider and the peak stick could be supplemented with the (hkl) values. This also applies to Figure 2.
The article is accepted for publication, but I would like to see the changes mentioned in points 1-4 before publication, therefore Major revision, no missing experiments .
Author Response
First and foremost, we would like to thank the Reviewers for their insightful comments. These comments, indeed, improved the paper content and presentation considerably, and we feel indebted to the Reviewers for the time spent for thorough and constructive review of the manuscript. Please find below the detailed responses to every comment made by each of the Reviewers. We sincerely hope that these detailed responses will fully satisfy the Reviewers as well as the Editor. All revisions to the manuscript are highlighted in the manuscript.
Reviewer 1
- when one speaks of Rietveld analysis, there is a program behind it, which one?
The following sentences were added to the section 2:
“Qualitative phase analysis was performed using PHAN program [28] and JCPDS (ICDD) data. Quantitative phase analysis and determination of the grain size were performed using full-profile Rietveld refinement method and PHAN% program [28].”
- for the structural data there is the PDF file of the ICDD or the freely available COD database. Therefore, this data should also be used for the evaluations and deviations should be shown. The crystal structure can also be created from the str or cif files for high-quality publications and should also be shown for better illustration. The crystal structure can then also be used to better explain the layer structures that often form in the elementary cells for the magnetic properties.
We used the JCPDS (a previous version of the ICDD) database, which is available to us. We have looked through the COD database, but it does not contain data on the phases of interest to us. We agree with dear reviewer that phase crystal structure image could beautify the manuscript text. However, we don’t deal with the crystal chemistry – the scientific field dealing with the construction of crystal structures of various phases. Unfortunately, the present work does not concern the layer crystal elementary cells and their influence on magnetic properties.
- Equation (2) is new to me; the Russian source is not available to me. This should be backed up with another source, because the results found here take up a lot of space and are very significant. The R-values determined can then be compared with the lists from the PDF or COD files.
The following sentences were added to the section 3.1:
“In accordance with fundamental concepts [31], x-ray scattering at amorphous solids having the topological order leads to the appearance of diffuse halo, whose intensity is determined by the Debye scattering equation:
, (2)
where fm, fn are the atomic scattering factors of atoms m, n, k is scattering vector and R is the nearest interatomic spacing in short-range order areas (the first coordination sphere). The series of the scattering intensity I maxima is determined by the series of sinkRmn/kRmn function maxima. Analysis of this function shows that it takes maximum values for argument values of kRmn = 7.73, 14.06, 20.46. Taking into account that k=4πsinθ/λ we obtain:
|
, |
(3) |
where θi is the angular position of i-th diffuse maximum.”
The R value characterizes the shortest distance between atoms in an amorphous material in the hard sphere random dense packing model, and the dhkl value characterizes the distance between adjacent parallel crystal planes in the crystal lattice. A comparison of these values was carried out in the book [Umansky, Y. S.; Skakov, J. N.; Ivanov, A. N.; Rastorguev, L. N. Crystallography, X-Ray and Electron Microscopy, Metallurgy, Moscow, USSR, 1982; 632p. in Russian] and in the monograph [Pastukhov, E.A., Vatolin, N.A., Lisin, V.L. et al. Diffraction studies of the structure of high-temperature melts. Yekaterinburg: Ural Branch RAS, 2003; 353p. In Russian]. For metal alloys, there is an empirical relation R = 1.23∙d1, where d1 is the interplanar distance for the first diffraction line of the crystalline phase.
The value of R = 0.25 nm (Table 1, estimated from the angular position of halo II in the presented work), is close to the value of 1.23∙dαFe(110) = 2.49 Å, calculated from the PDF data. Thus, the relation holds quite well for the materials studied.
- figure 1 could be drawn a little wider and the peak stick could be supplemented with the (hkl) values. This also applies to Figure 2.
Figures 1 and 2 were changed.
Reviewer 2 Report
Comments and Suggestions for Authors
The authors have a completed a systematic study of the effect of boron as a glass former. My only concerns are that there is no indication of how the composition was measured. Is the oxygen just surface passivation or is it dissolved into the sample. How do the annealed and as-grown films compare in composition to the original targets.
Author Response
First and foremost, we would like to thank the Reviewers for their insightful comments. These comments, indeed, improved the paper content and presentation considerably, and we feel indebted to the Reviewers for the time spent for thorough and constructive review of the manuscript. Please find below the detailed responses to every comment made by each of the Reviewers. We sincerely hope that these detailed responses will fully satisfy the Reviewers as well as the Editor. All revisions to the manuscript are highlighted in the manuscript.
Reviewer 2
My only concerns are that there is no indication of how the composition was measured.
The following sentences were added to the section 2:
“...and metallic (Ni-Cr alloy)...”
“The chemical composition of the films on glass substrates was determined by energy dispersive X-ray spectroscopy using a Hitachi S-3400N (Hitachi High-Technologies, Tokyo, Japan) scanning electron microscope equipped with a Noran 7 Thermo attachment. The film thickness was estimated using the cross-sectional electron micrographs. An accurate assessment of the content of light elements (B,O) was carried out for the films deposited on metallic (Ni-Cr) substrates by glow discharge optical emission spectroscopy (GDOES) using a Horiba Jobin Yvon Profiler 2 (Horiba Jobin Yvon, Longjumeau, France). The Ni-Cr substrates were used exclusively for GDOES measurements on the as-deposited films. The rest of the measurements were performed on the glass substrates.”
Is the oxygen just surface passivation or is it dissolved into the sample?
This issue is discussed in the last paragraph of section 3.1:
“It should be noted that all films contain the impurity oxygen (no more than 3 at %), which may originate from either the residual gas in the vacuum chamber (residual pressure is ~10–3 Pa), the working gas (Ar 99.9995% purity), or the cathode materials (SHS-prepared ceramic plates). Considering a high oxygen solubility in Ti (up to 33 at % in αTi) and a very high affinity of O to Ti (the heat of formation of titanium oxides is –Hf298 = 543-3405 kJ/mol), the influence of oxygen on the phase composition of the studied films cannot be neglected. Indeed, a small amount of the oxygen solid solution in titanium, αTi(O), was identified by us previously in the FeTiB film containing a small amount of Ti (2-3 at %) and O (1.1-3.8 at %) [27]. In the present study there are the films with the sufficiently higher Ti content (5 and 16 at %) and the higher volume fraction of the αFe(Ti) phase, and in this case it is likely that small amounts of the formed αTi(O) phase cannot be determined by XRD.”
How do the annealed and as-grown films compare in composition to the original targets?
The sputtering targets were prepared with Fe, Ti and B contents, which should be obtained in the deposited FeTiB films. In order to minimize the content of gas impurities in the resulting films, Fe (99.9% purity) and TiB2 ceramics with a porosity of 5% were used. The film chemical composition was studied on as-deposited films.
Reviewer 3 Report
Comments and Suggestions for Authors
In this manuscript entitled "Magnetron-deposited FeTiB films: From structural metastability to the specific magnetic state", the authors have studied a metastable phase state in the Fe73Ti5B19O3 and Fe55Ti16B27O2 films, which is formed upon magnetron deposition under preset conditions.
The annealed films were found to be characterized by nanocrystalline structure, which is represented by two crystalline phases, namely, the ferromagnetic solid solution αFe(Ti), and nonferromagnetic boride FenB.
the Fe73Ti5B19O3 films already in the deposited state are strong ferromagnets (the high saturation magnetization is Ms = 1.75±0.1 Т and the coercive field is Hc = 25±2 Oe).
The Fe55Ti16B27O2 films in the deposited state are superparamagnets with the coercive field Hс = 0.3±0.3 Oe
These results are important and interesting, but this paper has some shortcomings, which should be improved.
Some recently updated articles [H. Zhang, Y. Wang, H. Wang, D. Huo, W. Tan, J. Appl. Phys. 131 (2022) 043901; Yan Wang, Haiou Wang, Weishi Tan, Dexuan Huo, J. Appl. Phys. 132, 183907 (2022)] related to magnetic properties of other functional materials are suggested to be cited in this paper.
The authors claimed “...and experimental data on the magnetic structure and magnetic properties of the films are reported for the first time....”. However, there are no direct experimental data of magnetic structure in this paper, so it cannot be said that the experimental data of magnetic structure are reported for the first time. It is suggested that the author should either provide experimental data of magnetic structure or re-describe relevant contents to ensure accuracy!
The inset of Figure 4b, fitting by eq.(4) and eq.(5). Eq.(5) is not shown in paper. Please recheck it.
Author Response
First and foremost, we would like to thank the Reviewers for their insightful comments. These comments, indeed, improved the paper content and presentation considerably, and we feel indebted to the Reviewers for the time spent for thorough and constructive review of the manuscript. Please find below the detailed responses to every comment made by each of the Reviewers. We sincerely hope that these detailed responses will fully satisfy the Reviewers as well as the Editor. All revisions to the manuscript are highlighted in the manuscript.
Reviewer 3
Some recently updated articles [H. Zhang, Y. Wang, H. Wang, D. Huo, W. Tan, J. Appl. Phys. 131 (2022) 043901; Yan Wang, Haiou Wang, Weishi Tan, Dexuan Huo, J. Appl. Phys. 132, 183907 (2022)] related to magnetic properties of other functional materials are suggested to be cited in this paper.
The ceramic ferromagnets, the measurements of temperature dependences of different properties are not investigated in our work, so citing of these publications is not available.
The authors claimed “...and experimental data on the magnetic structure and magnetic properties of the films are reported for the first time....”. However, there are no direct experimental data of magnetic structure in this paper, so it cannot be said that the experimental data of magnetic structure are reported for the first time. It is suggested that the author should either provide experimental data of magnetic structure or re-describe relevant contents to ensure accuracy!
In the present work the subsections 3.4 and 3.5 are completely devoted to the experimental data on magnetic structures (superparamagnetic structure and stochastic domains, respectively). Indirect measurements of the parameters of the magnetic structure from the laws of approach to saturation magnetization and the analysis of the stochastic magnetic structure are described in detail in the refs. [50, 53-55], wherein [55] is our work.
The inset of Figure 4b, fitting by eq.(4) and eq.(5). Eq.(5) is not shown in paper. Please recheck it.
It was our carelessness. During the revision of the manuscript based on the Reviewer 1 recommendations, we added new Eq. (2) in subsection 3.1, so we believe that the unchanged figure 4b now matches the text.
Round 2
Reviewer 1 Report
Comments and Suggestions for Authors
The corrections are accepted and the article is ready for publication.
Author Response
Thank you for your high appreciation of our work.
Reviewer 3 Report
Comments and Suggestions for Authors
The authors are not very clear about the measurement methods required for experimental research on magnetic structures. The authors did not make any corrections to the previous suggestions. Due to academic errors, it is recommended to reject the manuscript
Author Response
Reply to Reviewer 3
- We greatly appreciate your professional review of our manuscript. We apologize to the respected Reviewer for the fact that in response to his comments written in the 1st Round of Review, we did not cover the experimental method used in our work for studying the magnetic microstructure of nanocrystalline soft magnetic materials (correlation magnetometry) in sufficiently clear detail. We are sending in response to the 2nd Round of Review a more detailed, compared to the previous (response to the 1st Round of Review), following description of the magnetic microstructure model, now included in the second paragraph in subsection 3.5 (highlighted in the manuscript):
The physical origin of exchange interaction between grains in nanocrystalline ferromagnets is explained by the random anisotropy model (RAM) [4, 53]. According to RAM, under conditions when the grain size 2Rc (or an area in amorphous phase, which is characterized by uniform magnetic anisotropy) is less than the exchange interaction length (A/K)1/2 (where A is exchange stiffness, K is magnetic anisotropy constant), the randomly oriented local magnetic anisotropy (on a grain scale 2Rc) is suppressed by exchange interaction on a scale of so-called stochastic domain 2RL. A stochastic domain is a magnetization autocorrelation area, size of which 2RL is determined by competition of local magnetic anisotropy field D1/2Ha (K = HaMs/2) and exchange stiffness A. The D value, easy-axis magnetic anisotropy dispersion, depends on the symmetry of local (within a grain) magnetic anisotropy; for the uniaxial magnetic anisotropy D = 1/15.
In the References section [50, 53-58, 61-65] we indicate a wider list of works in which this model and the method based on it are used. In addition, we have added a third paragraph to subsection 3.5 (highlighted in the manuscript), which provides literature data about the correlation magnetometry method and its possible applications. Here's the paragraph:
For the experimental measurement of the above-mentioned parameters of magnetic microstructure, there is a method for analyzing magnetization curves in high fields, so-called correlation magnetometry. This method began by the theoretical consideration of the autocorrelation function in the magnetic microstructure of amorphous and nanocrystalline ferromagnets in [54]. In relation to measurements of the parameters of the magnetic microstructure from the laws of approach to saturation magnetization, the foundations were laid in [55]. A theoretical consideration of the influence of such a magnetic microstructure on the behavior of various properties was begun in [56]. Note that during magnetization in high magnetic fields, the structural features of amorphous and nanocrystalline ferromagnets are reflected not only in the behavior of magnetization (on which the method of correlation magnetometry is based), but also in the optical properties [57], magnetoresistance [58, 59], magnetocaloric [60], and other properties. The current state of the correlation magnetometry method for analyzing magnetic microstructure is given in [53, 61]. To date, this method has become quite widespread [62-64].
- Regarding the Reviewer's remark “there are no direct experimental data of magnetic structure in this paper, so it cannot be said that the experimental data of magnetic structure are reported for the first time”, made in the 1st Round of Review. Thank you for pointing this out. We are very sorry for our carelessness and incorrect writing. Indeed, in our work there is no consideration of magnetic structure (by definition) as the ordered arrangement of magnetic spins. Therefore, thanks to the reviewer’s remark, in the article all references to the magnetic structure are replaced by magnetic microstructure (highlighted in the manuscript), as a generally accepted term. In addition, according to the scientific and technical literature available to us, a quantitative evaluation of the parameters of the stochastic magnetic domains in films of Fe-Ti-B system alloys has not been previously carried out anywhere except our research, which allowed us to write that “experimental data on the magnetic microstructure and magnetic properties of the Fe-Ti-B films are reported for the first time.”
- We regret that we were unable to refer to the very interesting and significant publications mentioned by the Reviewer in 1st Round of Review [H. Zhang, Y. Wang, H. Wang, D. Huo, W. Tan, J. Appl. Phys. 131 (2022) 043901; Yan Wang, Haiou Wang, Weishi Tan, Dexuan Huo, J. Appl. Phys. 132, 183907 (2022)], Now we refer to these works to give importance and commonality of the problems of studying the structure and properties of ferromagnets [59, 60].
4. We really hope that our response to the 2nd Round of Review, as well as what was indicated by the Reviewer in the 1st Round of Review “These results are important and interesting, but this paper has some shortcomings, which should be improved” will allow the respected Reviewer to give a positive rating of our article submitted for publication to Co
Author Response File: 
Author Response.pdf
Round 3
Reviewer 3 Report
Comments and Suggestions for Authors
The paper has been revised and can be accepted.
