oxide nanoparticles of fe-co-ni were prepared in six different compositions by co-precipitation method. the as-synthesized nanoparticles were characterized by x-ray diffraction (xrd), field emission scanning electron microscope (fesem), fourier transform infrared (ft-ir) and vibrating sample magnetometer  (vsm). it was found that the nanoparticles had mean crystalline size of 30-55 nm and spher...

We demonstrate theoretically that, by using external magnetic fields, one can imprint pointlike topological defects on the spin texture of a dilute Bose-Einstein condensate. The symmetries of the condensate order parameter render this topological defect to be accompanied with a vortex filament corresponding to the Dirac string of a magnetic monopole. The vorticity in the condensate coincides wi...

The mechanism of appearance of exponentially large number of metastable states in magnetic phases of disordered Ising magnets with short-range random exchange is suggested. It is based on the assumption that transitions into inhomogeneous magnetic phases results from the condensation of macroscopically large number of sparse delocalized modes near the localization threshold. The properties of m...

The potential of exploiting the spin of the electron (in addition to its charge) in novel new electronic devices and the associated opportunities for new science has led to extensive search for viable magnetic semiconductors with room temperature ferromagnetism (RTFM). Some success for ferromagnetism has been reported in dilute magnetic semiconductors (DMS) and dilute magnetic oxides (DMO) cont...

We develop a semiclassical method to calculate the density of magnetic monopoles in non-abelian gauge theories at finite temperature in the dilute gas approximation. This quantity is related to the inverse magnetic screening length for which we obtain μM = 0.255g T in SU(2).

L(2,3)-edge X-ray magnetic circular dichroism (XMCD) spectra have been measured for the well-defined dilute Ni(II) and Mn(II) ions doped into a MgO crystal, with sub-Kelvin dilution refrigerator cooling and 2 T magnetic field magnetization. A 30-element Ge array X-ray detector has been used to measure the XMCD for these dilute ions, whose concentrations are 1400 ppm for Ni(II) and 10,000 ppm fo...