Fe 2 O 3 nanoparticles embedded in a SiO 2 matrix have been synthesized by sol-gel chemistry and high temperature heat treatments. Virtually pure -Fe 2 O 3 (in excess of 93%) is obtained, although a two-phase mixture, -Fe 2 O 3 + R-Fe 2 O 3 , is observed for Fe 2 O 3 /SiO 2 ratios greater than 37 wt %. The -Fe 2 O 3 nanoparticles are stable up to ∼1600 K. Optimized -Fe 2 O 3 nanoparticles are ferrimagnetic, with a Curie temperature T C ≈ 510 K, and remarkably high values of room-temperature coercivity, H C ) 20 kOe.

A one-step process for the production of nanoparticles presenting advanced magnetic properties can be achieved using vapor condensation. In this paper, we report on the fabrication of Fe particles covered by a uniform MgO epitaxial shell. MgO has a lower surface energy than Fe, which results in a core-shell crystal formation. The particles are proven to be useful as as contrast agents for magnetic resonance diagnosis and heating mediators for cancer therapy through hyperthermia. They also have potential to be used in drug delivery and magnetic-activated cell sorting.Dear Editor, Enclosed is the paper "Self-assembled Multifunctional Fe/MgO Nanospheres for Magnetic Resonance Imaging and Hyperthermia" by Carlos Martínez-Boubeta et al. for your consideration as a potential contribution in the NanoMedicine. The manuscript, or any part of it, is not and will not be submitted elsewhere for publication while under consideration by Nanomedicine. All authors have seen and approved the submission of this manuscript.While a huge number of methods have been developed for the scalable synthesis and preparation of inorganic metal and semiconductor nanoparticles, only a few specialized techniques were reported for the preparation of coreshell nanoparticles. In this paper, we reported a novel and versatile technique for the preparation of injectable nanoparticle dispersions suitable to act as contrast agents for magnetic resonance imaging. Our ferromagnetic particles * Cover LetterWe wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.The manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us.We confirm that we have given due consideration to the protection of intellectual property associated with this work and that there are no impediments to publication, including the timing of publication, with respect to intellectual property. In so doing we confirm that we have followed the regulations of our institutions concerning intellectual property.We further confirm that any aspect of the work covered in this manuscript that has involved either experimental animals or human patients has been conducted with the ethical approval of all relevant bodies and that such approvals are acknowledged within the manuscript.Signed by all authors as follows:[LIST AUTHORS, and SIGNATURES dated on June 20 th , except otherwise stated]We suggest the following as the possible reviewers of this work: Jian-Ping Wang

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Both, virtual and printed 3D crystal models can help students and teachers deal with chemical education topics such as symmetry and point groups. In the present paper, two freely downloadable tools (interactive PDF files and a mobile app) are presented as examples of the application of 3D design to study point-symmetry. The use of 3D printing to produce tangible crystal models is also explored. A series of dissection puzzles that will be especially useful for teaching crystallographic concepts such as asymmetric unit and general/special positions is presented. Educators are encouraged to use the presented tools in their classes, and we expect our work to inspire other college educators to design and share similar tools.

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The widespread occurrence of a novel, high coercivity magnetic phase in well‐heated archeological material is reported. Its properties are defined when it represents the dominant magnetic phase, although it is nearly always found as part of a mixture of magnetic phases. They are as follows: very high coercivity (remanence coercivity >600 mT), low unblocking temperatures (≤200°C) and high degree of thermal stability–this last property distinguishing it from goethite. The phase shows striking similarities to magnetic phases produced by thermal decomposition of nontronite (an Fe‐rich clay), where decomposition occurs after prolonged heating in air to high temperatures – conditions suffered by well‐heated archeomagnetic material. Preliminary results of Mössbauer and X‐Ray diffraction spectroscopy suggest that the phase is more likely to be a substituted hematite, rather than Fe‐cristobalite or a variant of ɛ‐Fe2O3.

SUMMARY Secular variation ‘master’ curves are built up using geomagnetic historical observations or archaeomagnetic data from a limited area and their use is usually restricted to regions of around 1000 km radius. Relocation of data within this distance is a common practice to enable comparison of data, although the errors due to such process are rarely taken into account. A detailed analysis of the distribution of relocating geomagnetic data has been done using three popular sets of geomagnetic models (IGRF‐9, GUFM and CALS7K‐2). This study improves the error analysis of relocating geomagnetic directions made up to date and expands it to geomagnetic intensities. Maximum errors correlate with the non‐dipole to dipole field ratio. Archaeomagnetists could use this analysis to valuate the error introduced by reducing data.

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