Lattice Distortion Coupled with Magnetic Ordering in a Triangular Lattice Antiferromagnet CuCrO2

We investigated magnetostrictive properties of a triangular lattice antiferromagnet CuCrO2 showing an incommensurate proper-screw spin order by means of x-ray diffraction and strain gauge measurements. A deformation of the triangular lattice plane leading to a lowered crystallographic symmetry was found upon the magnetic ordering, which demonstrates a strong spin-lattice coupling in this system. The resultant multiple structural domains can be successfully arranged by magnetic field cooling procedures. We discuss the relationship between the lattice distortion and incommensurability in CuCrO2.