Nonequilibrium excitations in ferromagnetic nanoparticles

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.

Uniform excitations in magnetic nanoparticles

We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization and the magnetic hyperfine field, in contrast to the Bloch T(3/2) law in bulk materials. The temperat...

Uniform magnetic excitations in nanoparticles

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...

Current-induced excitations in single cobalt ferromagnetic layer nanopillars.

Current-induced excitations in Cu/Co/Cu single ferromagnetic layer nanopillars ( approximately 50 nm in diameter) have been studied experimentally as a function of Co layer thickness at low temperatures for large applied fields perpendicular to the layers. For asymmetric junctions current-induced excitations are observed at high current densities for only one polarity of the current and are abs...