  We succeeded in observing pressure-suppressed magnetic long range ordering
(LRO) in the triangular lattice antiferromagnet CuFeO$_{2}$, using neutron
diffraction experiments under an isotropic pressure. The magnetic LRO of the
four-sublattice ground state under ambient pressure in CuFeO$_{2}$ almost
disappears at the high pressure of 7.9 GPa, and is replaced by an
incommensurate order with temperature-independent wave number of (0.192 0.192
1.5). The incommensurate wave number observed at 7.9 GPa corresponds to that
observed just above the temperature at which lattice distortion and magnetic
LRO simultaneously occur under ambient pressure. Therefore, the long-range
magnetic ordering disappears because the high pressure suppressed the lattice
distortion that otherwise relieves spin frustration and leads the spin system
to LRO.
