Transition metal oxides magnetoresistance

Transition Metal Oxides Magnetoresistance and Half-Metallicity... 

The discovery in 1986 of high-temperature superconductivity in ceramic cuprates of perovskite structure started a period of very intensive research of transition metal oxides. Soon afterwards, in 1993, the colossal magnetoresistance effect was discovered in manganite perovskites, again leading to an increasing research activity in the field of magnetic oxides. It is... 

In this article, we discuss spin, charge and orbital orders in transition metal oxides, in particular, in the rare-earth manganites which have become famous since 1993 owing to the phenomenon of colossal magnetoresistance (CMR) exhibited by them (Rao Raveau 1998). We also touch upon the issue of electronic inhomogeneities we discuss the signatures of the presence of such inhomogeneities and theoretical approaches to understand the same. 

Nowadays these questions are in the focus of attention in the studies of the magnetic properties of the transition metal oxides and of the colossal magnetoresistance compounds in part. For the LaMnOa crystals the most consistent approach based on taking into account both the CJTE and the superexchange Hamiltonians was developed by Ishihara, Inoue, and Maekawa [35]. 

Transition metal oxides constitute an interesting and widely investigated class of compounds in solid state and materials chemistry. They form the basis of solid state chemistry for the study of structure, composition and various physical and chemical properties that are not only of fundamental importance, but have technological applications. The important properties of these materials include superconductivity, ferromagnetism, magnetoresistance, half-metallicity, catalysis, nonlinear optical property, ferroelectri-city and multiferroic property all are of current immense interest. 

Indeed complex behaviour for instance is well documented in systems with highly correlated electrons [4], like those which give rise to colossal magnetoresistance, or high To superconductors, two phenomena where magnetic properties play a key role. In general transition metal oxides provide a large variability of properties. However the traditional approach to these systems is of the top-down... 

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