Spin excitations in ferromagnetic manganites with orbital order

Spin excitations in ferromagnetic manganites

An effective one–band Hamiltonian for colossal–magnetoresistance (CMR) manganites is constructed and the spin excitations are determined. Fitting the experimental data by the derived spin–wave dispersion gives an eg–electron hopping amplitude of about 0.2 eV in agreement with LDA band calculations.

Evolution of spin-wave excitations in ferromagnetic metallic manganites.

Neutron scattering results are presented for spin-wave excitations of three ferromagnetic metallic A1-xA'xMnO3 manganites (where A and A' are rare- and alkaline-earth-metal ions), which when combined with previous work elucidate the systematics of the interactions as a function of carrier concentration x, on-site disorder, and strength of the lattice distortion. The long-wavelength spin dynamic...

Title Spin and orbital excitations in undoped manganites

Orbital-ordering-induced anomalous softening of the ferromagnetic spin waves in perovskite manganites

Spin wave excitations were measured in the ferromagnetic phase of Nd1/2Sr1/2MnO3 by neutron scattering. This compound is located in proximity to the A-type antiferromagnetic state, and it shows a clear anisotropy and anomalous softening of the spin wave excitations. The softening in the ferromagnetic phase is induced by the orbital ordering.

Evolution of the low-frequency spin dynamics in ferromagnetic manganites

Elastic and inelastic neutron scattering was used to study two ferromagnetic manganites A1−xBxMnO3 (x ≈ 0.3) with Tc=197.9 K and 300.9 K. The spin dynamical behavior of these is similar at low temperatures, but drastically different at temperatures around Tc. While the formation of spin clusters of size (∼ 20 Å) dominates the spin dynamics of the 197.9 K sample close to Tc, the paramagnetic to ...