  Two aspects in connection with the magnetic properties of
La_{2-x-y}Nd_ySr_xCuO_4 single crystals are discussed. The first is related to
long wavelength magnetic excitations in x = 0, 0.01, and 0.03 La_{2-x}Sr_xCuO_4
detwinned crystals as a function of doping, temperature and magnetic field. Two
magnetic modes were observed within the AF region of the phase diagram. The one
at lower energies was identified with the spin-wave gap induced by the
antisymmetric DM interaction and its anisotropic properties in magnetic field
could be well explained using a canonical form of the spin Hamiltonian. A new
finding was a magnetic field induced mode whose dynamics allowed us to discover
a spin ordered state outside the AF order which was shown to persist in a 9 T
field as high as 100 K above the N\'eel temperature T_N for x = 0.01. For these
single magnon excitations we map out the Raman selection rules in magnetic
fields and demonstrate that their temperature dependent spectral weight is
peaked at the N\'eel temperature. The second aspect is related to phononic and
magnetic Raman scattering in La_{2-x-y}Nd_ySr_xCuO_4 with three doping
concentrations: x = 1/8, y = 0; x = 1/8, y = 0.4; and x = 0.01, y = 0. We
observed that around 1/8 Sr doping and independent of Nd concentration there
exists substantial disorder in the tilt pattern of the CuO_6 octahedra in both
the orthorhombic and tetragonal phases which persist down to 10 K and are
coupled to bond disorder in the cation layers. The weak magnitude of existing
charge/spin modulations in the Nd doped structure did not allow us to detect
specific Raman signatures on lattice dynamics or two-magnon scattering around
2200 cm-1.
