The Mössbauer Effect: A Romantic Scientific Page

Round 1

Reviewer 1 Report

This manuscript is fluently written and offers an attractive introduction to the field of Mössbauer spectroscopy for an audience of metallurgists who wish to get acquainted with the historical origin, the basic principles and the possibilities of this spectroscopy.

There are no real shortcomings in this manuscript.  Apart from a few typo's I only have one minor scientific comment.

In paragraph 8 the author describes the basic hyperfine interactions that can be observed in a Mössbauer spectrum.  These are shown in Figure 9.   Figure 9(c) is described as "the magnetic interaction divides the spectrum into six lines".  However, the figure shows a spectrum which represents a mixed magnetic + quadrupole interaction.  The text is not wrong, but this point could be made clearer in the text and in the footnote, to avoid confusion with the reader.

Some of the typographical errors:

line 28: 1900 instead of '900

line 298: started instead of start

line 313 reaches instead of reach

line 420 what do you mean by "reticular symmetry" ?

line 426 3:2:1:1:2:3 instead of 3:2:1=1:2:3

line 523 the table mentions that the quadrupole moment can be measured (which is not strictly correct, except if the electric field gradient is known); it should also mention that the nuclear magnetic moment can be measured (here this is correct, since one can know and control the magnetic field)

line 538 "because they do not require" instead of "because do not require"

line 550 arrive instead of derive

line 604/605 and line 635/636 repeat the same comment "points out the influence of the surface energy on the transformation".  Maybe some rewording needed, as e.g. adding "also" the second time.

 

 

Author Response

Dear Reviewer,

Thank you very much for nice comments and precious suggestions and amendments.

With my best regards,

Gianni Principi

Reviewer 2 Report

The review article written by the famous Mossbauer scientist contains the basic underlying principles of the Mossbauer effect and the most spectacular illustrations of its applications in metallurgy. It is interesting to read the article especially the irritative description of the months before and immediately after the first observation of the recoilless effect in resonant nuclear absorption.

Anyhow I have some doubts if such interesting article is suitable for the MDPI Journal: Metals. It does not contain new results and relatively small amount of the references to the recent publications. The essential part of the article is the famous textbook knowledge.

But at the same time it can attract attention to the possibilities of the Mossbauer spectroscopy in the investigation of metal compounds.

So I guess that the decision should be taken by the Editors.

 

Some small corrections in the text.

Line 67            “5 parts on 10⁷. ” is not quite clear

Line 80            the exact value of the linewidth is not relevant in the estimation example

 

Line 110   “a partial overlap between emission and absorption lines occur even at room temperature. ” Is it really take place for 129Ir?

 

Line 393   I do not think that the picture presents “spectrometer” even schematically.

 

Line 399   A single resonance line indeed takes place in the absence of the hyperfine splitting but the next addition “i.e. if the electronic environment of resonant nuclei is the same in source and absorber. ”is not correct

 

Line 426    it is better to change “polarization” for “magnetization”

 

Line 433   “randomly oriented” is not the reason for the collapse of the sextet, it is due to the fluctuations

Line 448  “there is a combination of the interactions”  ? it is better to say that “There are several types of hyperfine fields in a sample”

 

Line 527  “The first consist” ? “The first one consists” ?

 

 

Line 543   “nn”   should be here written  “nearest neighbours (nn)”

 

Line 728  “a ferromagnetic sextet” it is better “a magnetic sextet” because oxides are typically antiferromagnetic or ferrimagnetic.

Author Response

Dear reviewer,

Thank you for comments and suggestions.

With my best regards,

Gianni Principi

Reviewer 3 Report

You give (i) a nice general description of the excitement of the discovery of the Mössbauer Effect followed by (ii) detailed applications to metallurgy, especially steels and corrosion.

The only suggestion for possible improvement I have is you might want to include briefly after (i) some of the early Mössbauer work on basic magnetism and isomer shifts laying the foundation for (ii). Most of the references are after about 1980 and I think it might help a newcomer to enter the field if you said a bit more than Fig. 9 on the spectra of alloys. Also though iron is probably the most interesting to metallurgists (and certainly the most important practically) there is some work on alloys of tin, antimony and other elements. 

You might want to give a reference for CEMS and CXMS.

An interesting story behind Ref. 19 is how Stan Hanna solved the puzzle of understanding the hyperfine spectrum when he realized the possibility that the ground state of ⁵⁷Fe had a negative magnetic moment. 

 

Author Response

Dear reviewer,

thank you for your comments.

A good reference for CEMS and CXMS is the quoted work by Longworth. The suggestion of including more basic physics are maybe beyond the scope of the article.

With my best regards,

Gianni Principi