  The effect of chemical substitution on the ground state of the geometrically
frustrated antiferromagnet CsCrF$_4$ has been investigated through a neutron
powder diffraction experiment. Magnetic Fe-substituted
CsCr$_{0.94}$Fe$_{0.06}$F$_{4}$ and nonmagnetic Al-substituted
CsCr$_{0.98}$Al$_{0.02}$F$_{4}$ samples are measured, and magnetic Bragg peaks
are clearly observed in both samples. Magnetic structure analysis revealed a
120$^{\circ}$ structure having a magnetic propagation vector $\mathbf{k}_{\rm
mag}=(0,0,1/2)$ in CsCr$_{0.94}$Fe$_{0.06}$F$_{4}$. For
CsCr$_{0.98}$Al$_{0.02}$F$_{4}$, a quasi-120$^{\circ}$ structure having
$\mathbf{k}_{\rm mag}=(1/2,0,1/2)$ is formed. It is notable that the identified
magnetic structure in CsCr$_{0.94}$Fe$_{0.06}$F$_{4}$ belongs to a different
phase of ground states from those in CsCr$_{0.98}$Al$_{0.02}$F$_{4}$ and the
parent CsCrF$_{4}$. These results suggest that the Fe-substitution strongly
influences the ground state of CsCrF$_{4}$.
