Tunable fabrication on iron oxide/Au/Ag nanostructures for surface enhanced Raman spectroscopy and magnetic enrichment

► A facile approach was developed to fabricate multifunctional Fe2O3/Au/Ag nanostructures. ► The composite nanostructures exhibited optimal magnetism and tunable SERS activities. ► The combination of magnetic enrichment and SERS improved the limit of SERS detection.