Superconductivity has again become a challenge following the discovery of unconventional superconductivity. Resistance-free currents have been observed in heavy-fermion materials, organic conductors and copper oxides. The discovery of superconductivity in a single crystal of UGe2, ZrZn2 and URhGe revived the interest in the coexistence of superconductivity and ferromagnetism. The experiments in...

Here, we report the synthesis and physical properties of Co2FeGe (CFG) Heusler alloy (HA) nanoparticles (NPs). The NPs size 23 nm are prepared using co-precipitation method. X-ray selected area electron diffraction patterns have confirmed cubic phase with A2-disorder. These soft ferromagnetic, exhibit a high saturation magnetization (Ms) along very Curie temperature (Tc) 1060 K. observed Tc val...

We investigate near-Fermi-energy (EF) element-specific electronic and spin states of ferromagnetic van der Waals (vdW) metal Fe5GeTe2. The soft x-ray angle-resolved photoemission spectroscopy (SX-ARPES) measurement provides spectroscopic evidence localized Fe 3d band. also find prominent hybridization between the band delocalized Ge/Te p bands. This picture is strongly supported from direct obs...

Diluted magnetic semiconductors possessing intrinsic static magnetism at high temperatures represent a promising class of multifunctional materials with high application potential in spintronics and magneto-optics. In the hexagonal Fe-doped diluted magnetic oxide, 6H-BaTiO3-δ, room-temperature ferromagnetism has been previously reported. Ferromagnetism is broadly accepted as an intrinsic proper...

The Hubbard model is a “highly oversimplified model” for electrons in a solid which interact with each other through extremely short ranged repulsive (Coulomb) interaction. The Hamiltonian of the Hubbard model consists of two pieces; Hhop which describes quantum mechanical hopping of electrons, and Hint which describes nonlinear repulsive interaction. Either Hhop or Hint alone is easy to analyz...

We describe the ferromagnetism in the manganese pyrochlores, such as Tl2Mn2O7 and Sc2Mn2O7 , in terms of the interplay between superexchange, Zener double exchange, and indirect exchange, the first being antiferromagnetic ~AF! while the last two are ferromagnetic. The tendency towards the antiferroalignment of the localized Mn spins is significantly weakened due to ~i! the presence of spin frus...

Using the constrained-path Monte Carlo method, we studied the magnetic properties of the two-dimensional periodic Anderson model for electron fillings between 1/4 and 1/2. We also derived two effective low-energy theories to assist in interpreting the numerical results. For 1/4 filling, we found that the system can be a Mott or a charge-transfer insulator, depending on the relative values of th...

Compositional, microstructural, and magnetic characterization of ZnO 30 Å /Mn x n multilayers prepared by sputtering is presented to study the observed ferromagnetism in the Mn-ZnO system. The nominal Mn layer thickness, x, is varied from 3 to 60 Å, while the number of bilayers, n, is increased to maintain the total amount of Mn constant. Microstructure information was deduced from x-ray reflec...

We report the observation of spatially separated Kondo scattering and ferromagnetism in anatase Ta0.06Ti0.94O2 thin films as a function of thickness (10-200 nm). The Kondo behavior observed in thicker films is suppressed on decreasing thickness and vanishes below ~25 nm. In 200 nm film, transport data could be fitted to a renormalization group theory for Kondo scattering though the carrier dens...