A comparative study of the electron- and hole-doped compositions of single crystalline $Nd_{1-x}Ca_{x}Mno_{3}$ (x = 0.6 and 0.4) by Brillouin scattering

Abstract

In order to understand the differences between the nature of the electron- and the hole-doped compositions of rare earth manganates, properties of single crystals of $Nd_{1-x}Ca_{x}MnO_{3}$ with x = 0.6 and 0.4 have been investigated. In the electrical resistivity measurements, the electron-doped (x = 0.6) composition shows no effect of magnetic field unlike the hole-doped (x = 0.4) composition, but both exhibit similar current-induced changes. Brillouin scattering studies show that the x = 0.6 and 0.4 compositions show softening of the modes on cooling the samples towards charge-ordering transitions. The strength of coupling between the $e_{g}$ orbitals and the elastic strain is considerably larger in the hole-doped composition containing a larger population of $Mn^{3+}$ ions