Abstract: A set of paramagnetic particles synthesized by co-precipitation methods wherein an alkaline hydroxide solution is mixed with a metal salt solution. The alkaline hydroxide features ammonium hydroxide, potassium hydroxide, sodium hydroxide, or mixtures thereof. The metal salt solution features at least one ferrous salt and at least one tetravalent metal salt selected from Group 4 elements of the Periodic Table. The concentration of the ferrous salt is equal to or greater than the concentration of the tetravalent metal salt. The paramagnetic particles may be used for bioprocessing via magnetic fields. Bioprocessing, for example, may include purifying, concentrating, or detecting biomolecules of interest (e.g., nucleic acids, carbohydrates, peptides, proteins, other organic molecules, cells, organelles, microorganisms, viruses, etc.), or other magnetic field-based processes common to applications in separation science, diagnostics, molecular biology, protein chemistry, and clinical practice.