Related papers: Photoinduced magnetism in the ferromagnetic semico…
Ferromagnetism is predicted in undoped diluted magnetic semiconductors illuminated by intense sub-bandgap laser radiation . The mechanism for photo-induced ferromagnetism is coherence between conduction and valence bands induced by the…
We propose a model of carrier-mediated ferromagnetism in semiconductors that accounts for the temperature dependence of the carriers. The model permits analysis of the thermodynamic stability of competing magnetic states, opening the door…
We predict a new mechanism of enhancement of ferromagnetic phase transition temperature $T_c$ in uniaxially stressed diluted magnetic semiconductors (DMS) of p-type. Our prediction is based on comparative studies of both Heisenberg…
The electronic and magnetic properties of concentrated and diluted ferromagnetic semiconductors are investigated by using the Kondo lattice model, which describes an interband exchange coupling between itinerant conduction electrons and…
The realization of semiconductors that are ferromagnetic above room temperature will potentially lead to a new generation of spintronic devices with revolutionary electrical and optical properties. Transition temperatures in doped ZnO are…
We investigate the magnetic and the transport properties of diluted magnetic semiconductors using a spin-fermion Monte-Carlo method on a 3D lattice in the intermediate coupling regime. The ferromagnetic transition temperature $T_c$ shows an…
Through time-resolved two-color magneto-optical Kerr spectroscopy we have demonstrated that photogenerated transient carriers decrease the coercivity of ferromagnetic InMnAs at low temperatures. This transient ``softening'' persists only…
We formulate a theory of doped magnetic semiconductors such as Ga$_{1-x}$Mn$_x$As which have attracted recent attention for their possible use in spintronic applications. We solve the theory in the dynamical mean field approximation to find…
We present a theoretical survey of ferromagnetic transition temperatures in cubic (III,Mn)V semiconductors based on a model with $S=5/2$ local moments exchange-coupled to itinerant holes in the host semiconductor valence band. Starting from…
By comparing the photo-induced magnetization dynamics in simple layered systems we show how light-induced modifications of the magnetic anisotropy directly enhance the magnetization. It is observed that the spin precession in…
We consider a superconductor-ferromagnet (S/F) structure and assume that above the superconducting transition temperature $T_{c}$ the magnetic moment exists only in F. {In a simple model of the ferromagnet (the exchange field is of the…
EuC$_2$ is a ferromagnet with a Curie-temperature of $T_C \simeq 15\,$K. It is semiconducting with the particularity that the resistivity drops by about 5 orders of magnitude on cooling through $T_C$, which is therefore called a…
Ferromagnetic superconductors, where ferromagnetism and superconductivity coexist despite their antagonism, exhibit strikingly diverse behaviors. Depending on the interplay between the ferromagnetic exchange field and the superconducting…
We theoretically investigate disorder effects on the ferromagnetic transition ('Curie') temperature $T_c$ in dilute III$_{1-x}$Mn$_x$V magnetic semiconductors (e.g. Ga$_{1-x}$Mn$_x$As) where a small fraction ($x \approx 0.01-0.1$) of the…
Recent materials research has advanced the maximum ferromagnetic transition temperature in semiconductors containing magnetic elements toward room temperature. Reaching this goal would make information technology applications of these…
For modeling the magnetic properties of concentrated and diluted magnetic semiconductors, we use the Kondo-lattice model. The magnetic phase diagram is derived by inspecting the static susceptibility of itinerant band electrons, which are…
The temperature-driven reorientation transition which, up to now, has been studied by use of Heisenberg-type models only, is investigated within an itinerant-electron model. We consider the Hubbard model for a thin fcc(100) film together…
We present a theory of carrier-induced ferromagnetism in diluted magnetic semiconductors (III_{1-x} Mn_x V) which allows for arbitrary itinerant-carrier spin polarization and dynamic correlations. Both ingredients are essential in…
We report on the observation of ultrafast photo-enhanced ferromagnetism in GaMnAs. It is manifested as a transient magnetization increase on a 100-ps time scale, after an initial sub-ps demagnetization. The dynamic magnetization enhancement…
We suggest an approach to account for spatial (composition) and thermal fluctuations in "disordered" magnetic models (e.g. Heisenberg, Ising) with given spatial dependence of magnetic spin-spin interaction. Our approach is based on…