K. El Maalam

The effects of synthesis conditions on the magnetic properties of zinc ferrite spinel nanoparticles

Zinc ferrite nanocrystals were synthesized from metal chloride precursors via chemical co-precipitation method, using different synthesis conditions. Characterization measurements including X-ray diffraction (XRD), transmission electron microscopy (TEM) and super conductiong quantum device (SQUID) were used to study the influence of precursors concentration and reaction time on the crystalline structure, average sizes and magnetic properties of zinc ferrite nanoparticles. The transmission images show spherical, homogenous shape and particle size ranging from 16 to 22 nm. DC magnetization (2-300 K) measurements reveal a superparamagnetic behavior for the ZnFe2O4 samples with a blocking temperature in the range of 18-24 K. Our results demonstrate that magnetic properties of magnetic particles can be largely modified by just changing the reaction condition such as concentration and reaction time, which might be a useful way to design novel magnetic materials.

First-principles study of electronic, electrical and optical properties of HoMn2O5

In this work, we have studied the electronic, electrical and optical properties of HoMn2O5 using first-principles density functional theory within the generalized gradient approximation (GGA). The electrical conductivity decreases with increasing temperature and it exhibits metal-like behavior. The maximum conductivity values as a function of relaxation time reach 11,44.1022 (Q-1m-1s-1) at 300 K. The optical calculation presents this material a good absorbing light in the visible region which is good for many optoelectronic and photovoltaic applications.

Phase diagrams and magnetic properties of double perovskite Ba2CrMoO6

In this paper, the Monte Carlo simulation (MCS) and the mean field approximation (MFA) methods have been used to study the magnetic properties of double perovskite Ba2CrMoO6 in the framework of the Ising model, which is important for a better understanding of the magnetic behavior of this material. This compound is constituted of two magnetic cubic sublattices: one occupied by Mo5+ and other occupied Cr3+, the critical exponents and phase diagrams for this compound are determined. The critical behavior, compensation temperature and susceptibility are also determined.