Recent reports of the detecting of ferromagnetism and superconductivity in ruthenium-cuprates have aroused great interest. Unfortunately, whether the two antagonistic phenomena coexist in the same space in the compounds remains unresolved. By employing the magneto-optical-imaging technique, ferromagnetism and superconductivity were indeed directly observed to coexist in the same space in RuSr2(...

using fe(no3)3.9h2o, co(no3)2.6h2o and mn(no3)2.4h2o the magnetic properties of nanoparticles trimetalic iron - cobalt - manganese, with supported magnesium oxide have been prepared by co-precipitation and solvothermal methods. the prepared samples are characterized by scanning electron microscope (sem), x-ray diffraction (xrd), vibrating sample magnetometer (vsm) and brunaer-emmett-teller (bet...

We revisit Nagaoka ferromagnetism in the two-dimensional U = ∞ Hubbard model using the dynamical mean-field theory (DMFT). A recently developed continuous time quantum Monte Carlo method is applied to solve the DMFT impurity problem. The stability of Nagaoka ferromagnetism is studied as a function of both the nearest-neighbor lattice hopping t and the next-nearest-neighbor lattice hopping t. It...

The control of ferromagnetism by light at room temperature is essential for the development of some optical-magnetic coupling devices, data storage and quantum computation techniques. In the present work, we demonstrate that the ferromagnetism of a semiconducting ZnO film on Pt substrate can be controlled by nonpolarized ultraviolet or violet light. The illumination of light with sufficiently h...

The recent discovery of ferromagnetism above room temperature in low-temperature-processed MnO(2)-ZnO has generated significant interest. Using suitably designed bulk and thin-film studies, we demonstrate that the ferromagnetism in this system originates in a metastable phase rather than by carrier-induced interaction between separated Mn atoms in ZnO. The ferromagnetism persists up to approxim...

The chalcopyrite CdGeP2 doped with Mn have been recently found to exhibit room-temperature ferromagnetism. Isovalent substitution of the Cd site is expected, however, to create antiferromagnetism, in analogy with the well-known CdTe:Mn (d5) case. However, chalcopyrite semiconductors exhibit low-energy intrinsic defects. We show theoretically how ferromagnetism results from the interaction of Mn...

The interplay of ferromagnetism and superconductivity is obviously a topic of great fundamental and practical interest. Specifically, weak ferromagnetism was recently reported to coexist with superconductivity in heavy-fermion specimens.1–3 Even more recently, the discovery that ferromagnetism exists together with superconductivity in high-temperature superconductors (HTSC) of the EuCeRuSrCuO f...

Electric-field control of ferromagnetism in magnetic semiconductors at room temperature has been actively pursued as one of the important approaches to realize practical spintronics and non-volatile logic devices. While Mn-doped III-V semiconductors were considered as potential candidates for achieving this controllability, the search for an ideal material with high Curie temperature (T(c)>300 ...

Ferromagnetism in the Hubbard model with an infinite-range hopping. Abstract We prove, as recently conjectured, that the ground state of the Hub-bard Hamiltonian with an infinite-range hopping, when the number of electrons N e = N + 1 (N being the number of sites), is ferromagnetic fully polarized. Despite its long history, the problem of itinerant ferromagnetism is still, to many regards, an o...