Raman scattering evidence of a disordered structural phase transition in La1.475Nd0.4Sr0.125CuO4 - art. no. 092103

We report the temperature dependence of the polarized Raman scattering inte nsity for a single-crystal sample of La1.475Nd0.4Sr0.125CuO4 which is known to exhibit antiphase stripe magnetic/charge order below T similar or equal to 30 K. In zz polarization conditions, the soft mode associated with the tilts/distortions of the (La/Nd/Sr)(2)CuO6 structural units hardens signifi cantly, narrows, and this peak becomes asymmetric as the orthorhombic-tetra gonal transition is approached from above. Below the structural transition this mode softens significantly and the peak becomes more symmetric. A near by mode, associated with the bending of the cations, shows a splitting belo w this transition. Several additional modes are also observed in zz and yy polarization conditions. We discuss these results in terms of structural di sorder in the doped (La/Sr/Nd)(2)CuO4 system.