  Out-of-time-order correlators (OTOCs) progressively play an important role in
different fields of physics, particularly in the non-equilibrium quantum
many-body systems. In this paper, we show that OTOCs can be used to prob the
Floquet dynamical quantum phase transitions (FDQPTs). We investigate the OTOCs
of two exactly solvable Floquet spin models, namely: Floquet XY chain and
synchronized Floquet XY model. We show that the border of driven frequency
range, over which the Floquet XY model shows FDQPT, signals by the global
minimum of the infinite-temperature time averaged OTOC. Moreover, our results
manifest that OTOCs decay algebraically in the long time, for which the decay
exponent in the FDQPT region is different from that of in the region where the
system does not show FDQPTs. In addition, for the synchronized Floquet XY
model, where FDQPT occurs at any driven frequency depending on the initial
condition at infinite or finite temperature, the imaginary part of the OTOCs
become zero whenever the system shows FDQPT.
