Scalar and spinor quasinormal modes of an $f(R)$ global monopole

The quasinormal modes for scalar and spinor fields in the background spacetime corresponding to an $f(R)$ global monopole are calculated using the WKB approximation. In the obtained results we emphasize the role played by the parameter ${\psi }_0$, associated with the $f(R)$ gravity. We discuss the appropriate limit ${\psi }_0\to 0$, in which case the results concerning to the Schwarzschild black hole are obtained, as it should be expected.