The temperature dependences of the thermoelectric power, TEP,(S) and magnetoresistance (MR) effect of La1-xLixMnOy (x= 0.05, 0.1, 0.15, 0.2 & 0.25 at%) fixed valence doped compounds were studied between 80K and 320K. X-ray powder diffraction (XRD) showed that the samples are single phase. We found the correlation of structures to the magnetoresistance (MR) and the thermoelectric power (S) which we ... Read more

Landau theory is used to investigate the behavior of a metallic magnet driven toward a quantum critical point by the application of pressure. The observed dependence of the transitiontemperature with pressure is used to show that the coupling of the magnetic order to the lattice diverges as the quantum critical point is approached. This means that a first order transition ... Read more

We have investigated the volume collapse occurring in LaMnO3 unit cell using the anisotropic Potts mode modified by two types of anisotropic interactions which has been used to study the behavior of the orbital-ordering configurations with temperature. The bond lengths are related to the occupation of the orbits. We have shown that the collapse is due to the change of ... Read more

A dynamic model of the asymmetric Ising glass is presented: an Ising model with antiferromagnetbonds, −J">−J−J, and ferromagnetic bonds, +J">+J+J, with probabilities q">qq and 1−q">1−q1−q. The dynamics is introduced by changing the arrangement of the antiferromagnetic bonds after n">nn Monte Carlo steps but keeping the same value of q">qq and spin configuration. In the region where there is a second ... Read more

ABSTRACT Zirconium oxynitride films were deposited onto glass and Si (1 0 0) substrates at room temperature by pulsed reactive dc magnetron sputtering of a metallic Zr target in an Ar/O2/N2 atmosphere. The structural, compositional and optical properties of the deposited films were found to depend on the ratio of nitrogen partial pressure to the total reactive gas partial pressure. ... Read more

The thermoelectric power and Hall measurement carried out on the asprepared sample of Ga0. 45 In0. 55 Sb confirmed that the sample is n-type semiconductor. The existence of two minima at 3.5 and 4.8 Vcm-1 on the σ-E characteristic reflects the occurrence of the Gunn effect. A metallic like behavior of the sample is observed and interpreted. The effect of ... Read more

We have made the first detailed Faraday measurements on thin films of Fe3O4 for 10 Read more

The optical properties of a small magnetic cluster are studied in a magnetic version of the Frank–Condon principle. This simple model is considered to show new basic physics and could be adopted to treat real problems. The energies and wavefunctions of the cluster are calculated for different spin configurations to evaluate the energies and the strengths of the allowed transitions ... Read more

The Jahn-Teller distortive transition of LaMnO3 is described by a modified three-state Potts model. The interactions between the three possible orbits depends both on the orbits and their relative orientation on the lattice. Values of the two exchange parameters which are chosen to give the correct low temperature phase and the correct value for the transition temperature are shown to ... Read more

A study is made of an anisotropic Potts model in three dimensions where the coupling depends on both the Potts state on each site and also the direction of the bond between them using both analytical and numerical methods. The phase diagram is mapped out for all values of the exchange interactions. Six distinct phases are identified. Monte Carlo simulations ... Read more