  We report the magnetotransport properties of ferromagnet (FM)/antiferromagnet
(AFM) Fe$_2$CrSi/Ru$_2$MnGe epitaxial bilayers using current-in-plane
configurations. Above the critical thickness of the Ru$_2$MnGe layer to induce
exchange bias, symmetric and asymmetric curves were observed in response to the
direction of FM magnetocrystalline anisotropy. Because each magnetoresistance
curve showed full and partial AFM rotation, the magnetoresistance curves imply
the impact of the Fe$_2$CrSi magnetocrystalline anisotropy to govern the AFM
rotation. The maximum magnitude of the angular-dependent resistance-change
ratio of the bilayers is more than an order of magnitude larger than that of
single-layer Fe$_2$CrSi films, resulting from the reorientation of AFM spins
via the FM rotation. These results highlight the essential role of controlling
the AFM rotation and reveal a facile approach to detect the AFM moment even in
current-in-plane configurations in FM/AFM bilayers.
