The inventive concepts presented herein relate to methods of identifying molecules identification of molecules using apparatuses including: electromagnetic write-head(s); magneto-resistive read sensor(s), and processor(s). An exemplary method includes magnetically exciting a molecule to be identified using an alternating magnetic field generated by an electromagnetic write-head, measuring a resonant response of the molecule to be identified using a magneto-resistive read sensor; and comparing, using a processor, the resonant response of the molecule to be identified with a table of known resonant responses to identify a chemical composition of the molecule to be identified. The molecule to be identified may optionally be disposed on a biosample substrate which comprises, or is coupled to, a plurality of servo-alignment marks; and the plurality of servo-alignment marks are configured to facilitate alignment of the electromagnetic write-head with the biosample tracks of the biosample substrate.