  It is widely believed that magnetars could be born in core-collapse
supernovae (SNe), binary neutron star (BNS) or binary white dwarf (BWD)
mergers, or accretion-induced collapse (AIC) of white dwarfs. In this paper, we
investigate whether magnetars could also be produced from neutron star--white
dwarf (NSWD) mergers, motivated by FRB 180924-like fast radio bursts (FRBs)
possibly from magnetars born in BNS/BWD/AIC channels suggested by \cite{mar19}.
By a preliminary calculation, we find that NSWD mergers with unstable mass
transfer could result in the NS acquiring an ultra-strong magnetic field via
the dynamo mechanism due to differential rotation and convection or possibly
via the magnetic flux conservation scenario of a fossil field. If NSWD mergers
can indeed create magnetars, then such objects could produce at least a subset
of FRB 180924-like FRBs within the framework of flaring magnetars, since the
ejecta, local environments, and host galaxies of the final remnants from NSWD
mergers resemble those of BNS/BWD/AIC channels. This NSWD channel is also able
to well explain both the observational properties of FRB 180924-like and FRB
180916.J0158+65-like FRBs within a large range in local environments and host
galaxies.
