Structural and Magnetotransport Transitions in the Electron-Doped Pr_1-xSr_xMnO₃ (0.85 ≤ x ≤ 1) Manganites

Abstract

The exploration of the Mn4+-rich side of the Pr1 - x Sr x MnO3 system has allowed the extension of the domain of the cubic perovskite, by using a two-step process, combining synthesis under Ar flow at high temperature and O2 pressure annealing at lower temperature. We show that these Pr-doped cubic perovskites exhibit a coupled structural (cubic-tetragonal) and magnetic (para-antiferro) transition connected with a resistivity jump at the same temperature. The strong interplay between lattice, charges, and spins for these oxides results from the appearance at low temperature of the distorted C-type antiferromagnetic structure. The Pr1 - x Sr x MnO3 magnetic phase diagram shows, for 0.9 ≤ x < 1 (i.e., on the Mn4+-rich side), the existence at low temperature of C- and G-type antiferromagnetism. The absence of ferromagnetic−antiferromagnetic competition explains that magnetoresistante properties are not observed in this system, in contrast to Mn4+-rich Ln1 - x Ca x MnO3 systems.

Raman spectroscopy on cubic and hexagonal SrMnO3

“…7,8 The sample synthesized in air is characterized by a hexagonal structure. The oxygendeficient cubic compound was obtained in Ar-flow.…”

Phase separation and magnetoresistivity inSm0.1Ca0.9−xSrxMnOMartin1, Maignan2, Hervieu3 et al. 2008Phys. Rev. BSelf Cite9280View full textAdd to dashboardCite

“…In fact, it is well known that for such compounds ͑close to SrMnO 3 ͒, syntheses in reducing atmosphere are needed to avoid the hexagonal phases. [17][18][19] This part of the diagram being not of first importance for this study, no new samples have been prepared in the adequate conditions. The x dependence of the cell parameters and unit cell volume is shown Fig.…”

Near Fermi level electronic structure ofPr1−xSrxMnO3: Photoemission study

“…Resistivity and magnetic behavior of the samples have been studied using the four probe technique and SQUID magnetometry. Details of the sample preparation, characterization and structural studies are published elsewhere along with a phase diagram 17,21,22 . Angle integrated ultraviolet photoemission measurements were performed using an Omicron mu-metal UHV system equipped with a high intensity vacuum-ultraviolet source (HIS 13) and a hemispherical electron energy analyzer (EA 125 HR).…”