Synthesis of CMR manganites and ordering phenomena in complex transition metal oxides

Autor*innen

• Haifeng Li

Parameter

• Lehrbücher
• Universitätslehrbücher

Mehr zum Buch

This dissertation addresses the development of instrumentation and the optimization of polycrystalline materials synthesis, focusing on the single crystal growth of perovskite manganites. It includes the determination of crystal and magnetic structures from x-ray and neutron powder diffraction data of CMR La1-xSrxMnO3 manganites, correlating structural and magnetic properties. The study employs resonant soft x-ray scattering to explore complex ordering phenomena in La7/8Sr1/8MnO3 and La1Sr2Mn2O7 at transition metal and rare earth edges. Two innovative devices have been created: a rotating specimen holder for laboratory x-ray powder diffraction, which minimizes preferred orientation issues and produces a ‘zero-background’ contribution to data, and a miniature goniometer for resonant soft x-ray scattering, allowing for sample adjustments and improving efficiency in scattering chambers. The synthesis of materials is crucial in condensed matter physics, and a successful route has been developed for high-quality polycrystalline La7/8Sr1/8MnO3 samples through double calcining and sintering. This method is also applicable to La1Sr2Mn2O7 and La0.83Ca0.17MnO3, establishing a universal approach for testing. Additionally, a technique for creating straight, uniformly densified feed rods with a homogeneous composition has been achieved, facilitating the growth of large, high-quality single crystals.

• Sprache: Englisch
• Erscheinungsdatum: 2008
• Einband: Paperback