Provided herein are systems, methods, and compositions for magnetic nanoparticles and bulk nanocomposite magnets.

A bulk permanent magnetic material may include between about 5 volume percent and about 40 volume percent Fe.sub.16N.sub.2 phase domains, a plurality of nonmagnetic atoms or molecules forming domain wall pinning sites, and a balance soft magnetic material, wherein at least some of the soft magnetic material is magnetically coupled to the Fe.sub.16N.sub.2 phase domains via exchange spring coupling. In some examples, a bulk permanent magnetic material may be formed by implanting N+ ions in an iron workpiece using ion implantation to form an iron nitride workpiece, pre-annealing the iron nitride workpiece to attach the iron nitride workpiece to a substrate, and post-annealing the iron nitride workpiece to form Fe.sub.16N.sub.2 phase domains within the iron nitride workpiece.

A method for producing a nanoheterostructured permanent magnet includes a first step of preparing a raw material solution by dissolving, in a solvent, (1) a block copolymer comprising polymer block components that are immiscible but linked to each other, (2) a first inorganic precursor which is one of a hard magnetic material precursor and a soft magnetic material precursor, and (3) a second inorganic precursor which is the other of the hard magnetic material precursor and the soft magnetic material precursor, and a second step including a phase-separation treatment for forming a nanophase-separated, a conversion treatment for converting the hard magnetic material precursor and the soft magnetic material precursor to a hard magnetic material and a soft magnetic material, respectively, and a removal treatment for removing the block copolymer from the nanophase-separated structure.

A nanoheterostructured permanent magnet includes a hard magnetic material and a soft magnetic material of which one inorganic component is a matrix, and of which the other inorganic component is three-dimensionally and periodically arranged in the matrix, in a shape selected from the group consisting of a spherical shape, a columnar shape, and a gyroid shape, the nanoheterostructured permanent magnet having a three-dimensional periodic structure whose average value of one unit length of a repeated structure is 1 nm to 100 nm.

A bulk permanent magnetic material may include between about 5 volume percent and about 40 volume percent Fe.sub.16N.sub.2 phase domains, a plurality of nonmagnetic atoms or molecules forming domain wall pinning sites, and a balance soft magnetic material, wherein at least some of the soft magnetic material is magnetically coupled to the Fe.sub.16N.sub.2 phase domains via exchange spring coupling. In some examples, a bulk permanent magnetic material may be formed by implanting N+ ions in an iron workpiece using ion implantation to form an iron nitride workpiece, pre-annealing the iron nitride workpiece to attach the iron nitride workpiece to a substrate, and post-annealing the iron nitride workpiece to form Fe.sub.16N.sub.2 phase domains within the iron nitride workpiece.

Provided herein are systems, methods, and compositions for magnetic nanoparticles and bulk nanocomposite magnets.

A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

An apparatus for solidifying liquid in a magnetic field includes a magnetic circuit applying the magnetic field greater than or equal to about 1 tesla to a solidified part.

A spin transfer oscillator (STO) with a seed/FGL/spacer/SIL/capping configuration is disclosed with a composite seed layer made of Ta and a metal layer having a fcc(111) or hcp(001) texture to enhance perpendicular magnetic anisotropy (PMA) in an overlying (A1/A2).sub.YFeCo laminated field generation layer (FGL). The spin injection layer (SIL) may be laminated with a (A1/A2).sub.XFeCo configuration. The FeCo layer in the SIL is exchanged coupled with the (A1/A2).sub.X laminate (x is 5 to 50) to improve robustness. The (A1/A2).sub.Y laminate (y=5 to 30) in the FGL may be exchange coupled with a high Bs layer to enable easier oscillations. A1 may be one of Co, CoFe, or CoFeR where R is a metal, and A2 is one of Ni, NiCo, or NiFe. The STO is typically formed between a main pole and trailing shield in a write head.