
412 Biosensors Based on Nanomaterials and Nanodevices
comparable to the thermal energy. Therefore, the magnetic moment can point virtu-
ally in any direction. Therefore, electron precession becomes allowed and has to be
accounted for.
There are two main contributions to the overall spin relaxation: (1) Curie relaxation,
which is diffusion into the inhomogeneous nonuctuating magnetic eld created by the
mean crystal moment, aligned in the direction of B
0
; (2) Néel relaxation (uctuations of the
electronic magnetic moment). Principally, the Curie relaxation accounts for the high eld
part of the longitudinal relaxation rate proles (NMRD), where ...