  Using the quasiclassical Green's function formalism, we study the influence
of the odd-frequency spin-triplet superconductivity on the local density of
states (LDOS) in a diffusive ferromagnet (DF) attached to a superconductor.
Various possible symmetry classes in a superconductor are considered which are
consistent with the Pauli's principle: even-frequency spin-singlet even-parity
(ESE) state, even-frequency spin-triplet odd-parity (ETO) state, odd-frequency
spin-triplet even-parity (OTE) state and odd-frequency spin-singlet odd-parity
(OSO) state. For each of these states, the pairing state in DF is studied.
Particular attention is paid to the study of spin-singlet s-wave and
spin-triplet p-wave superconductors as the examples of ESE and ETO
superconductors. For spin-singlet case the magnitude of the OTE component of
the pair amplitude is enhanced with the increase of the exchange field in DF.
When the OTE component is dominant at low energy, the resulting LDOS in DF has
a zero energy peak (ZEP). On the other hand, in DF / spin-triplet p-wave
superconductor junctions LDOS has a ZEP in the absence of the exchange field,
where only the OTE paring state exists. With the increase of the exchange
field, the ESE component of the pair amplitude induced in DF is enhanced. Then,
the resulting LDOS has a ZEP splitting. We demonstrate that the appearance of
the dominant OTE component of the pair amplitude is the physical reason of the
emergence of the ZEP of LDOS.
