Structural, transport, magnetic properties and Raman spectroscopy of orthorhombic Y$1-x$CaxMnO3(0 <= x <= 0.5)

Abstract

Orthorhombic Y${}_{1-x}$Ca${}_x$MnO${}_3$ ($0\le x\le 0.5$) was prepared under high pressure and the variations with $x$ of its structural, magnetic, electrical properties and the polarized Raman spectra were investigated. The lattice parameters change systematically with $x$. Although there are strong indications for increasing disorder above $x=0.20$, the average structure remains orthorhombic in the whole substitutional range. Ca doping increases conductivity, but temperature dependence of resistivity $\rho$(T) remains semiconducting for all $x$. The average magnetic exchange interaction changes from antiferromagnetic for $x<0.08$ to ferromagnetic for $x>0.08$. The evolution with $x$ of the Raman spectra provides evidence for increasingly disordered oxygen sublattice at $x\ge 0.10$, presumably due to quasistatic and/or dynamical Jahn-Teller distortions.

arXiv comment13 pages, 8 figures

References in corpus (2)

• Determinative Role of the Jahn-Teller Disorder in the Raman Scattering of Mixed-Valence Manganites
• Short range ferromagnetism and spin glass state in ${\mathrm{Y}}_{0.7}\mathrm{C}{\mathrm{a}}_{0.3}\mathrm{Mn}{\mathrm{O}}_3$