Magnetic superlattice peaks are observed in single-crystal neutron-diffraction measurements on orthorhombic (Formula presented) at reciprocal points of (1/2±ε,1/2,0) and (1/2,1/2±ε,0) in the tetragonal notation where (Formula presented)0.126(Formula presented)0.003. The La NMR measurement reveals a broadening of the field-swept spectrum below (Formula presented)45 K corresponding to the existence of magnetic order. The remarkable softening of longitudinal sound waves along  is observed in the same crystal. The features observed in the neutron diffraction, NMR, and ultrasonic measurements suggest that the dynamical incommensurate spin correlation is pinned by a lattice instability toward the low-temperature tetragonal phase.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 1998|
ASJC Scopus subject areas