A stoichiometric LaSrMnRuO 6 perovskite was synthesized by a modified sol-gel method. Special precautions were taken to minimize loss of ruthenium during the synthesis. LaSrMnRuO 6 crystallizes with an orthorhombic perovskite structure in space group Imma determined by synchrotron powder X-ray diffraction; the Mn/Ru cations are disordered. A small amount of a Pmnb phase observed along with the major phase by electron diffraction transformed to Imma under the electron beam. X-ray absorption near-edge spectroscopy established the formal oxidation states as Mn 3+ and Ru 4+. Magnetic studies show ferromagnetic ordering at a Curie temperature of 225 K and an anomaly at 80 K. The magnetization, at 5 K in a field of 5 T, is not completely saturated and yields 2 μ B per formula unit, much lower than the 6 μ B expected. Electronic-transport measurements indicate semiconductor behavior with activation energies of 19.1 meV in the 230-380 K region and 22.7 meV in the 60-180 K region. A magnetoresistance of -6% is observed near the Curie temperature in a field of 5 T.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry