Physical property measurement System

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We apply for a low-maintainance cryogen-free magnetic device with a 9 T magnet with modular measurement options: ac and dc susceptibility, vibrating sample magnetometer, standard temperature range 2-400 K and oven option up to 1000 K, electrical conductivity, thermal conductivity, specific heat, magnetic measurements under high-pressure conditions and dilatometry. Magnetochemistry and Inorganic Solid State Chemistry are two supporting pillars in the natural science faculty of the Westfälische Wilhelms-Universität. Besides synthesis and structural characterization of new solids, the study of structure-property relationships plays a central role for a full understanding of the materials. The contributing groups are topically broadly based. The substance classes cover rare earth and transition metal based intermetallic compounds, ionic conductors, battery materials, thermoelectrics, photoresponsice materials, minerals and organic radicals. The different measurement modules of the PPMS are required for addressing the varying materials properties. The basic magnetochemical characterization (temperature- and field-dependent susceptibility and magnetization measurements) will most widely be used. The applicant group has long-term experience in this field and will share this expertize with all collaborating groups. For an innovative extension for the magnetochemical characterization we wish to install a high-pressure cell (up to 1.3 GPa), for samples from geosciences (expertise in the Klemmegroup) and for intermetallics. In parallel to the magnetic measurements, specific heat data will be measured, in order to get quantitative data for magnetic and structural phase transitions. This concerns intermetallic rare earth compounds, several organic radicals and samples from geosciences as well as ionic conductors. Electrical resistivity will be used as complementary tool for the basic characterization (metallic and semiconducting compounds). For magnetically ordering compounds, resistivity measurements give additional information on the ordering temperature and with respect to spin-disorder-scattering. This option will be used in the whole temperature range up to 400 K. Thermal conductivity measurements are essential for the characterization of thermoelectric materials (expertise in the Zeier group). Also these measurements will be conducted routinely up to 400 K. Further interesting projects concern thermal expansion. This is an important parameter for structural and magnetic phase transitions of intermetallic compounds as well as for lattice anharmonicity of ionic conductors and thermoelectrics. The new dilatometer allows to address these questions.