(CaMn)MnTeO - An Anomalously Stable High-Pressure Double Perovskite.

High pressure high temperature treatments of the composition CaMnMnTeO are found to yield only an ABB'O-type double perovskite (CaMn)MnTeO, rather than a AA'BB'O double double perovskite with A- and B- site cation order as found in analogs CaMnMnReO and CaMnMnWO with similar cation sizes. Double perovskite (CaMn)MnTeO adopts a monoclinic structure in space group P2/n with a framework of highly tilted MnO and TeO octahedra enclosing disordered Ca and Mn cations. Magnetic measurements show that (CaMn)MnTeO is a highly frustrated spin glass with a freezing transition at 5 K, and no long-range spin order is apparent by neutron diffraction at 1.

Ultrasmall superparamagnetic iron oxide nanoparticles for enhanced tumor penetration.

The intrinsic pathological characteristics of tumor microenvironments restrict the deep penetration of nanomedicines by passive diffusion. Magnetophoresis is a promising strategy to improve the tumor penetration of nanomedicines aided by the external magnetic propulsive force. However, the research thus far has been focused on large nanoparticles, while ultrasmall superparamagnetic iron oxide (FeO) nanoparticles (<∼20 nm) exhibit better performance in many applications such as cancer diagnosis and treatment.

A New Cation-Ordered Structure Type with Multiple Thermal Redistributions in Co InSbO.

Cation ordering in solids is important for controlling physical properties and leads to ilmenite (FeTiO ) and LiNbO type derivatives of the corundum structure, with ferroelectricity resulting from breaking of inversion symmetry in the latter. However, a hypothetical third ABO derivative with R32 symmetry has never been observed. Here we show that Co InSbO recovered from high pressure has a new, ordered-R32 A BCO variant of the corundum structure.

Double Double to Double Perovskite Transformations in Quaternary Manganese Oxides.

Control of cation ordering in ABX perovskites is important to structural, physical and chemical properties. Here we show that thermal transformations of AA'BB'O double double perovskites, where both A and B sites have 1:1 cation order, to (A A' ) BB'O double perovskites with fully disordered A/A' cations can be achieved under pressure in CaMnMnWO and SmMnMnTaO , enabling both polymorphs of each material to be recovered. This leads to a dramatic switch of magnetic properties from ferrimagnetic order in double double perovskite CaMnMnWO to spin glass behaviour in the highly frustrated double perovskite polymorph.

Lock-in spin structures and ferrimagnetism in polar NiCoScSbO oxides.

The new phase CoScSbO and NiCoScSbO solid solutions adopt the polar NiTeO-type structure and order magnetically below 60 K. A series of long-period lock-in [0 0 1/3n] spin structures with n = 5, 6, 8 and 10 is discovered, coexisting with a ferrimagnetic [0 0 0] phase at high Co-contents. The presence of electrical polarisation and spontaneous magnetisations offers possibilities for multiferroic properties.