Charles University
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Extreme Conditions Facilities
Chemistry and Material Sciences
Measurements of a rich spectrum of physical properties of materials in a wide range of temperatures, magnetic and electrical fields, and hydrostatic uniaxial pressures. The MGML technology facilities are enabling controlled preparation and characterization of high-quality samples (single crystals and polycrystals) of materials of various types which is available to users who have not their own well-characterized samples needed for measurements.
For single crystal growth and characterization. Optical floating zone furnace(Crystal Systems Corp. Japan) provide high quality single crystals by the optical floating zone method. Four ellipsoidal mirrors hold the same focus point (4 halogen lamps up to 1000 W each) in common while the sample bar can be melt under uniform temperature profile. Atmosphere (0-10 bar): Ar, N2, O2, air, vacuum Ttri-arc furnaceis used for the modified Czochralski single crystal growth method.Main parts of the furnace: Vacuum Chamber, water cooled copper crucible (Vakuum Praha), 3 electrodes, pulling head (Crystlex), pumping system (Pfeifer). Protective atmosphere: argon Solid State Electrotransport (SSE)is used to refine pure elements (Rare earth metals and uranium) as well as single crystals of intermetallic compounds (mainly prepared by the Czochralski technique). The SSE technique involves passing a direct electrical current through a metallic rod held between two electrodes. The impurities migrate under the influence of electric filed towards one end of the sample - the purity of the central part of the sample is increased. To prevent the sample contamination (oxidation) the experiment is held under UHV. Main parts of the apparatus: UHV chamber with pumping system, a direct current source Solution growth.(metalic fluc growth)\ POWDER DIFFRACTOMETERBruker D8 Advance UNIVERSAL POWDER and SINGLE CRYSTAL DIFFRACTOMETER Rigaku R-Axis Rapid.
magnetization - VSM (2 – 1000 K magnetization, susceptibility – AC/DC (0.4 [a.u.] - 2 – 400 K specific heat capacity (0.4 – 400 K thermal conductivity (2 – 400 K Seebeck effect (2 – 400 K electrical resistivity (0.4 – 400 K) Hall resistivity (0.4 – 400 K thermal expansion, magnetostriction (2 – 400 K electrical capacity, permitivity (2 – 400 K Properties measured with concurrent application of hydrostatic pressure (p3GPa)electrical resistivity, magnetic susceptibility [a.u.], thermal expansion, heat capacity [a.u.] Properties measured with concurrent application of uniaxial pressure: electrical resistivity.
magnetization - VSM (2 – 1000 K magnetization, susceptibility – AC/DC (0.4 [a.u.] - 2 – 400 K specific heat capacity (0.4 – 400 K thermal conductivity (2 – 400 K Seebeck effect (2 – 400 K electrical resistivity (0.4 – 400 K) Hall resistivity (0.4 – 400 K thermal expansion, magnetostriction (2 – 400 K electrical capacity, permitivity (2 – 400 K Properties measured with concurrent application of hydrostatic pressure (p3GPa)electrical resistivity, magnetic susceptibility [a.u.], thermal expansion, heat capacity [a.u.] Properties measured with concurrent application of uniaxial pressure: electrical resistivity.
magnetic susceptibility (AC) (1.9 - 400K); 0.01 - 1000 Hz, sensitivity 2 x 10-8 emu magnetization (DC) (1.9 - 400K); sensitivity 2 x 10-8 emu magnetoelectric response (1.9 – 400K, -50 - 50V) Properties measured with concurrent application of hydrostatic pressure(p1GPa): magnetization, magnetic susceptibility Properties measured with concurrent application of uniaxial pressure: magnetization, magnetic susceptibility.
Furnaces for sample growth and treatment; Characterization techniques; Supporting equipment
Measurements (in magnetic fields up to 9 T and temperatures down to 50 mK) of: Electrical resistivity AC susceptibility Heat capacity Thermal expansion.