  We consider the electromagnetic field near an interface between two media
with arbitrary real frequency-dependent permittivities and permeabilities,
under conditions supporting the surface plasmon-polariton (SPP) propagation.
The dispersion of the electric and magnetic properties is taken into account
based on the recent approach for description of the spin and momentum of
electromagnetic field in complex media [Phys. Rev. Lett. 119, 073901 (2017);
New J. Phys., 19, 123014 (2017)]. It involves the Minkowski momentum
decomposition into the spin and orbital parts with the dispersion-modified
permittivities and permeabilities. Explicit expressions are derived for spatial
densities of the energy, energy flow, spin and orbital momenta and angular
momenta of the transverse-magnetic (TM) SPP field. They are free from
non-physical singularities; the only singular contribution describes a strictly
localized surface part of the spin momentum that can be associated with the
magnetization current in the conductive part of the SPP-supporting structure.
On this ground, a phenomenological theory of the SPP-induced magnetization
(predicted earlier based on the simplified microscopic approach) is outlined.
Possible modifications and generalizations, including the transverse-electric
(TE) SPP waves, are discussed.
