A method for producing a sintered rare-earth magnet characterized by sintering a raw material that includes a ribbon-shaped polycrystalline phase with an average grain size of 10 to 200 nm fabricated by rapid solidification of an alloy melt having a rare-earth magnet composition, and a low-melting point phase formed on the surface of the polycrystalline phase and having a melting point lower than the polycrystalline phase.

Articles comprises iron oxide colloidal nanocrystals arranged within chains, wherein the chains of nanocrystals are embedded within a material used to form the article or a transfer medium used to transfer a color to the article are described. The material or transfer medium includes elastic properties that allow the nanocrystals to display a temporary color determined by the strength of an external force applied to the article, and the material or transfer medium includes memory properties that cause the displayed temporary color to dissipate when the external force is removed, wherein the dissipation of the displayed temporary color is sufficiently slow as to be visually observable by an average observer's unaided eye.

Apparatuses for manipulating a color displayed by an article of wear comprising iron oxide colloidal nanocrystals arranged within chains are described, The apparatus includes (a) a magnetic field source, wherein a strength of a magnetic field generated by the magnetic field source is tunable to control the color displayed by the article of wear, and (b) an energy source, wherein energy generated by the energy source is applied to at least some of the chains of nanocrystals to soften materials within the article of wear immediately surrounding the chains of nanocrystals to which the energy is applied.

Articles of wear comprises iron oxide colloidal nanocrystals arranged within chains are described. The chains of nanocrystals display a color that is determined by a strength of a magnetic field applied to the chains of nanocrystals, wherein the color is maintained when the magnetic field is removed.

A magnetic particle-polymer hybrid material can include: a substance having a structure of Formula 1 or derivative or salt thereof: Z(L-FP).sub.m (Formula 1), wherein: Z is a magnetic particle smaller than 1 mm; m is a positive integer and defines the number of (L-FP) coupled to the Z; L is a linker linked to the magnetic particle; FP is a functionalized polymer having: a first structure derived from a first norbornene compound linked to the magnetic particle through the L; and one or more monomeric units each including a second structure derived from a second norbornene compound, where one of the monomeric units is linked to the first structure through a saturated or unsaturated alkyl, each monomeric unit includes a functional group capable of binding with another substance.