We present a complex fluorescence study of a series of gadolinium oxide polycrystalline powders singly, doubly and triply doped with trivalent rare earth ions (Er3+, Tb3+, and Dy3+), to explore a possibility of their use as materials for white light emitting diodes. The excitation and luminescence spectra along with the decay kinetics were measured in the temperature range from 6 to 300 K. The luminescence efficiency was studied within the visible spectral range, i.e. −400 nm to 750 nm under excitation by 355 nm third harmonic Nd:YAG laser pulses.

The powder samples were sintered at 800∘C for 2 h in order to develop the stable hexagonal phase, characteristic of the SrFe12O19 structure. The consequences of Pb substitution (at iron sites) on various structural parameters like lattice constants, unit cell volume, crystallite size, and porosity have been discussed. Fourier transform infrared frequency bands were utilized to determine the formation of tetrahedral and octahedral clusters of M-type ferrites.

In this paper, we are presenting the effects of pressure using cold isostatic press (CIP) on the physical properties of nano-SiC-doped bulk sample Mg1.15B1.96C0.04. Effects on lattice parameters, critical current density (Jc), upper critical field (Bc2), irreversibility field (Birr), grain connectivity, anisotropy, and flux pinning force maximum as a function of the pressure have been thoroughly investigated. X-ray diffraction (XRD) analysis shows that a and c lattice parameters are decreased due to the CIP. The mass density of the pressed samples is increased.

The paper reports the JC(H, T ) of nano-ZnO doped MgB2 samples calculated from M–H loop measurements. Volume pinning forces at different temperatures have been evaluated as a function of the field from the JC–H data. Two different scaling laws, one by Fietz and Webb and another one by M. Eisterer, are used here to analyze the pinning forces. All samples show the scaling behavior, which confirms the existence of grain boundary pinning. The XRD and R–T data show the substitution of Zn at Mg sites. The anisotropy in the sample is found to decrease with the doping of the nano-ZnO.

The effect of the ball milling time (BMT) on the substitution of the carbon in the glucose doped MgB2 samples is investigated here. Using in situ solid state reaction, four different doped samples of Mg(B.98C.02)2 were prepared by mixing powders of Mg, boron and glucose for 2 h, 4 h, 8 h and 12 h using planetary ball milling. A reference sample of un-doped MgB2 was also prepared under same conditions. The particle size distribution of the un-reacted samples show a decrease in the particle size as the BMT is increased.