Composite nanoparticles and methods for making the same

A composite fine particle comprising:

• a first magnetic material;
• and
• a second material in contact with said first magnetic material, said second material being suitable for optical characterization of a material and/or plasmon coupling, wherein said composite fine particle is formed by laser ablation of a bulk composite material in a liquid, wherein said bulk composite material comprises said first magnetic material and said second material,
• wherein said composite fine particle comprises a core/shell structure comprising at least two cores of a first composition and a shell of a second composition, wherein said shell surrounds at least a portion of said cores,
• wherein said first magnetic material contains at least one of Cr, Mn, Fe, Co, Ni, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm.

A composite fine particle comprising:

• a first magnetic material;
• and
• a second material in contact with said first magnetic material, said second material being suitable for optical characterization of a material and/or plasmon coupling, wherein said composite fine particle is formed by laser ablation of a bulk composite material in a liquid, wherein said bulk composite material comprises said first magnetic material and said second material,
• wherein said composite fine particle comprises a core/shell structure comprising at least two cores of a first composition and a shell of a second composition, wherein said shell surrounds at least a portion of said cores,
• wherein said second material is selected from Au, Ag, Cu, Pt, Pd, and/or their alloys.

A composite fine particle comprising:

• a first magnetic material;
• and
• a second material in contact with said first magnetic material, said second material being suitable for optical characterization of a material and/or plasmon coupling, wherein said composite fine particle is formed by laser ablation of a bulk composite material in a liquid, wherein said bulk composite material comprises said first magnetic material and said second material,
• wherein said composite fine particle comprises a core/shell structure comprising at least two cores of a first composition and a shell of a second composition, wherein said shell surrounds at least a portion of said cores,
• wherein said liquid is selected from:
• water, alcohol, and an organic solvent, wherein said liquid contains zero, one or more chemical additives comprising surfactants, reduction agents, ligands, and stabilizers.

A method of preparing composite nanoparticles, comprising:

• ejecting material from a bulk target material using a physical energy source comprising a pulsed laser, said bulk target material comprising a first magnetic material and a second material disposed in a liquid;
• forming composite nanoparticles by cooling at least a portion of ejected material in said liquid, said composite nanoparticles characterized by having, in a nanoscale regime:
• a combination of said first magnetic material and said second material, said second material in contact with said first magnetic material, said second material being suitable for optical characterization of a material and/or plasmon coupling;
• and
• collecting at least a portion of said composite nanoparticles.