  Quantum metrology is studied in the presence of quantum correlation. The
quantum correlation measure based on quantum Fisher information enables us to
gain a deeper insight on how quantum correlations are instrumental in setting
metrological precision. Our analysis shows that not only the entanglement but
also the quantum correlation plays important roles to enhance precision in
quantum metrology. Even in the absence of entanglement, quantum correlation can
be exploited as the resource to beat standard quantum limit and reach
Heisenberg limit in metrology. Clearly unraveling the role of quantum
correlations, the tighter bounds on the metrological precision are derived.
