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Magnetic nanoparticles based on Fe3O4 were prepared by a facile and rapid one-pot solvothermal synthesis using FeCl3·6H2O as a source of iron ions, ethylene glycol as a solvent and NH4Ac, (NH4)2CO3, NH4HCO3 or aqueous NH3 as precipitating and nucleating agents. In contrast to previous reports we reduce the synthesis time to 30 minutes using a pressurized microwave reactor without the requirement of further post-treatments such as calcination. Dramatically reduced synthesis time prevents particle growth via Ostwald ripening thus the obtained particles have dimensions in the range of 20 to 130 nm, they are uniform in shape and exhibit magnetic properties with saturation magnetization ranging from 8 to 76 emu g(-1). The suggested method allows simple particle size and crystallinity tuning resulting in improved magnetic properties by changing the synthesis parameters, i.e. temperature and nucleating agents. Moreover, efficiency of conversion of raw material into the product is almost 100%.

An international journal to further the chemical sciencesRSC Advances is an international, peer-reviewed, online journal covering all of the chemical sciences, including interdisciplinary fields.The criteria for publication are that the experimental and/ or theoretical work must be high quality, well conducted adding to the development of the field.Thank you for your assistance in evaluating this manuscript. Guidelines to the refereesReferees have the responsibility to treat the manuscript as confidential. Please be aware of our Ethical Guidelines, which contain full information on the responsibilities of referees and authors, and our Refereeing Procedure and Policy.It is essential that all research work reported in RSC Advances is well-carried out and wellcharacterised. There should be enough supporting evidence for the claims made in the manuscript. When preparing your report, please:• comment on the originality and scientific reliability of the work • state clearly whether you would like to see the article accepted or rejected and give detailed comments (with references, as appropriate) that will both help the Editor to make a decision on the article and the authors to improve it Please inform the Editor if:• there is a conflict of interest • there is a significant part of the work which you are not able to referee with confidence • the work, or a significant part of the work, has previously been published • you believe the work, or a significant part of the work, is currently submitted elsewhere • the work represents part of an unduly fragmented investigationFor further information about RSC Advances, please visit: www.rsc.org/advances or contact us by email: advances@rsc.org. Enclosed please find the manuscript entitled "Novel synthesis of core-shell urchin-like ZnO coated carbonyl iron microparticles with enhanced magnetorheological activity". The paper is intended for publication in RSC advances if you consider it suitable. We believe that this article describing novel synthesis of inorganic-inorganic core-shell particles with unique urchin-like morphology having extraordinary rheological properties under applied magnetic field and further, exhibiting considerably enhanced sedimentation and thermo-oxidation stability with great potential in wide areas of industrial applications. We also hope that article is matching with the scope of your journal categories "Inorganic" and "Rheology and colloids" and is attractive enough in the same time. Sincerely yours Miroslav Mrlík et al. (Corresponding author)E-mail: mrlik@ft.utb.cz tel: +420 57 603 8128, fax: +420 576 031 444 ABSTRACTThe overall stability (thermo-oxidation, sedimentation) of the MR suspensions is a crucial problem decreasing their potential applicability in the real life. In this study the unique functional coating of carbonyl iron (CI) particles with ZnO structures was presented in order to develop new MR suspension based on the core-shell ZnO/CI urchin-like dispersed particles. The two-step synthesis provides the suitable core-shell particles wit...

Herein, we presented electromagnetic interference shielding characteristics of NiFe2O4 nanoparticles—in-situ thermally-reduced graphene oxide (RGO)—polypropylene nanocomposites with the variation of reduced graphene oxide content. The structural, morphological, magnetic, and electromagnetic parameters and mechanical characteristics of fabricated nanocomposites were investigated and studied in detail. The controllable composition of NiFe2O4-RGO-Polypropylene nanocomposites exhibited electromagnetic interference (EMI) shielding effectiveness (SE) with a value of 29.4 dB at a thickness of 2 mm. The enhanced EMI shielding properties of nanocomposites with the increase of RGO content could be assigned to enhanced attenuation ability, high conductivity, dipole and interfacial polarization, eddy current loss, and natural resonance. The fabricated lightweight NiFe2O4-RGO-Polypropylene nanocomposites have potential as a high performance electromagnetic interference shielding nanocomposite.

In this work, nickel ferrite (NiFe2O4) nanoparticles were synthesized by dextrin from corn-mediated sol–gel combustion method and were annealed at 600, 800, and 1000 °C. The structural and physical characteristics of prepared nanoparticles were studied in detail. The average crystallite size was 20.6, 34.5, and 68.6 nm for NiFe2O4 nanoparticles annealed at 600 °C (NFD@600), 800 °C (NFD@800), and 1000 °C (NFD@1000), respectively. The electromagnetic interference shielding performance of prepared nanocomposites of NiFe2O4 nanoparticles (NFD@600 or NFD@800 or NFD@1000) in polypropylene (PP) matrix engineered with reduced graphene oxide (rGO) have been investigated; the results indicated that the prepared nanocomposites consisted of smaller-sized nickel ferrite nanoparticles exhibited excellent electromagnetic interference (EMI) shielding characteristics. The total EMI shielding effectiveness (SET) for the prepared nanocomposites have been noticed to be 45.56, 36.43, and 35.71 dB for NFD@600-rGO-PP, NFD@800-rGO-PP, and NFD@1000-rGO-PP nanocomposites, respectively, at the thickness of 2 mm in microwave X-band range (8.2–12.4 GHz). The evaluated values of specific EMI shielding effectiveness (SSE) were 38.81, 32.79, and 31.73 dB·cm3/g, and the absolute EMI shielding effectiveness (SSE/t) values were 388.1, 327.9, and 317.3 dB·cm2/g for NFD@600-rGO-PP, NFD@800-rGO-PP, and NFD@1000-rGO-PP, respectively. The prepared lightweight and flexible sheets can be considered useful nanocomposites against electromagnetic radiation pollution.