First referee's report
…………

However, I have a few criticisms and suggestions that the authors must consider prior to publication:
a) The manuscript, at least some sections, is rather poorly written. For instance, the description of optical properties is very difficult to read. Sometimes, I had to guess what the authors really meant. They should carefully proof read the manuscript and correct the style.
b) Usually, one of the most serious difficulties with the work on coated nanoparticles is precisely showing that the nanoparticles have been efficiently coated by the metal. In the present manuscript, the main supporting evidence comes from a) EDS and XPS spectra that reveal the presence of metallic ……, and b) the UV spectra. As I said, these results are rather convincing. Yet, if the coating is so good, I would also expect that the magnetic properties will remain unchanged for long storage periods. Did the authors check the reproducibility of the magnetic properties (e.g. the saturation magnetization) after say 1 months, six months, etc?
c) The authors might consider referring to some early works reporting the synthesis and characterization of ……coated Fe nanoparticles, which are not in their reference list: P. Paul et al., Eur. Phys. J. D ……);.

In my opinion, the manuscript can be published once the authors have introduced the corrections suggested above.




Second referee's report


In my judgement, the following two points should be dealt with before consideration for publication:

1. The paper is not well written and has many English mistakes. It is also not well organized. This makes it very hard to understand.

2. The authors claimed that the ……sample is superparamagnetic but gave no evidence of that. The magnetization measurements presented in Figure 7 do not prove that the sample is superparamagnetic. Additional magnetization experiments are needed such as magnetization-versus-temperature measurements at constant low field after zero-field cooling.

#1：
The manuscript reports a novel approach to the synthesis of magnetite nanoparticles surrounded by a thin layer of Au. Taking into account the interest that these nanoparticles might have for science and for some future technologies, the results seem to be of sufficient interest to be published in Nanotechnology. Since the authors have appropriately taken my comments into consideration, I see no objection for the manuscript to be published. Yet, some additional work on the text would be desirable.
#2：
The authors revised the article and conducted additional experiments. I am satisfied with it now and recommend it for publication in your journal.



这篇文章IF>3,哈

兄弟，虽然有炫耀之疑，但还是祝贺。
中国人要让世界认识到我们也有不少好东西。