Anthony Arulraj

Charge ordering in the rare earth manganates: the experimental situation

Charge-ordered phases of rare earth manganates are novel manifestations arising from interactions between the charge carriers and phonons, giving rise to the localization of carriers at specific sites in the lattice below a certain temperature. Accompanying this phenomenon, the Mn 3+ (e g ) orbitals and the associated lattice distortions also exhibit long range ordering (orbital ordering). What makes the manganates even more interesting is the occurrence of complex spin ordering related to anisotropic magnetic interactions. In this article, we discuss the emerging scenario of charge-ordered rare earth manganates in the light of specific case studies and highlight some of the new experimental findings related to spin, orbital and charge ordering. We also examine features such as the charge stripes and phase separation found experimentally in these materials, and discuss the factors that affect charge-ordering such as the size of A-site cations and magnetic and electric fields, as well as isotopic and chemical substitutions.

Charge ordering in the rare-earth manganates: the origin of the extraordinary sensitivity to the average radius of the A-site cations,

The charge ordering in

Giant magnetoresistance, charge-ordering and related aspects of manganase oxides

Nd_{0.5}Sr_{0.5}MnO_3 (\langle r_A\rangle = 1.24 \AA),

Effect of substituting Ru4+ and other tetravalent ions in the B-site of rare earth manganates on the magneto-transport properties and charge-ordering

which occurs on cooling the ferromagnetic metallic ground state, is readily destroyed on application of a magnetic field of 6 T. For

Giant anisotropic magnetostriction in Pr0.5Sr0.5MnO3

Y{0.5}Ca_{0.5}MnO_3 (\langle r_A\rangle = 1.13 \AA),

Collapse of the charge ordering gap of Nd0.5Sr0.5MnO3 in an applied magnetic field

for which the ground state is charge ordered, on the other hand, magnetic fields have no effect on the charge ordering. In order to understand such a marked difference in charge-ordering behaviour of the manganates, we have investigated the structure as well as the electrical and magnetic properties of

Charge ordering in electron-doped manganates

Ln_{0.5}Ca_{0.5}MnO_3

Electrical transport, magnetism, and magnetoresistance in ferromagnetic oxides with mixed exchange interactions: A study of the

compositions (Ln D Nd, Sm, Gd and Dy) wherein

La_{0.7}Ca_{0.3}Mn_{1-x}Co_xO_3

\langle r_A\rangle

system

varies over the range