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The Interplay of the Chemical, Orbital and Spin Disorder in Ca2-xLaxMnRuO6 Perovskites

Soliz, Jennifer Rose

Abstract Details

2009, Master of Science, Ohio State University, Chemistry.
Perovskites and perovskite-related materials have been well studied over the past decades and found to exhibit fascinating properties. In particular, the main goal of this work is to understand the fundamental properties between manganese and ruthenium. New perovskites that have been synthesized and characterized are the Ca2-xLaxMnRuO6 solid solutions. These orthorhombic (Pnma) structures have been identified as phase pure samples with compositions of x = 1.2, 1.0, 0.8, 0.6, 0.4, and 0.2. Through Rietveld refinements from X-ray powder diffraction (XRPD), no cation ordering was found to occur on either the A-site or B-site; hence completely disordered perovskites. All compounds exhibit the a-b+a- octahedral tilt system. The lattice parameters from XRPD suggest that all samples lack the cooperative Jahn-Teller distortion (JTD). Although this was confirmed from the neutron powder diffraction (NPD) data gathered, the NPD data also designates that these structures have a local JTD that controls the magnetism. Using representational analysis, these samples were determined to have ferromagnetic spin structures. From the vibrating sample magnetometer (VSM) data, the susceptibility measurements indicate that all the samples are robust, ferromagnetic-like ordered structures with Curie temperatures ranging between 240-300 K despite the complete lack of long range Mn/Ru order. The saturation moments (~1.532 – 2.245 Bohr magnetons/f.u.) are reduced for full ferromagnetic ordering. Interestingly, the electrical conductivity decreases as more lanthanum is doped with the calcium end member. This doping gives rise to what appears as two classes of materials. One set is metallic and more conductive, while the other set is non-metallic and stronger insulators.
Patrick Woodward (Advisor)
Claudia Turro (Committee Member)
125 p.

Recommended Citations

Citations

  • Soliz, J. R. (2009). The Interplay of the Chemical, Orbital and Spin Disorder in Ca2-xLaxMnRuO6 Perovskites [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253094110

    APA Style (7th edition)

  • Soliz, Jennifer. The Interplay of the Chemical, Orbital and Spin Disorder in Ca2-xLaxMnRuO6 Perovskites. 2009. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1253094110.

    MLA Style (8th edition)

  • Soliz, Jennifer. "The Interplay of the Chemical, Orbital and Spin Disorder in Ca2-xLaxMnRuO6 Perovskites." Master's thesis, Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253094110

    Chicago Manual of Style (17th edition)