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Synthetic copper(ii) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(ii) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have the composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(ii) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar-gas reveals that the material contains no crystal water and reduces to pure Cu at 295 °C. Magnetic susceptibility measurements in the temperature range from 2 K to 300 K show intriguing paramagnetic behaviour with no sign of magnetic order down to 2 K. A crystal structure investigation is made based on powder diffraction data using one neutron diffraction pattern obtained at 5 K (λ = 1.5949(1) Å) combined with one conventional and two synchrotron X-ray diffraction patterns obtained at ambient temperature using λ = 1.54056, 1.0981 and λ = 0.50483(1) Å, respectively. Based on the X-ray synchrotron data the resulting crystal structure is described in the monoclinic space group P21/c (#14) in the P121/n1 setting with unit cell parameters a = 5.9598(1) Å, b = 5.6089(1) Å, c = 5.1138 (1) Å, β = 115.320(1)°. The composition is CuC2O4 with atomic coordinates determined by FullProf refinement of the neutron diffraction data. The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns obtained for both kinds of radiation show

We report that the spin structure of alpha-Fe2O3 nanoparticles rotates coherently out of the basal (001) plane at low temperatures when interacting with thin plate-shaped NiO nanoparticles. The observed spin reorientation (up to similar to 70 degrees) in alpha-Fe2O3 nanoparticles has, in appearance, similarities to the Morin transition in bulk alpha-Fe2O3, but its origin is different-it is caused by exchange coupling between aggregated nanoparticles of alpha-Fe2O3 and NiO with different directions of easy axes of magnetization.

Short range order of amorphous Mg60Cu30Y10 was investigated by x-ray and neutron diffraction, Cu and Y K-edge x-ray absorption fine structure measurements, and the reverse Monte Carlo simulation technique. We found that Mg-Mg and Mg-Cu nearest neighbor distances are very similar to values found in crystalline Mg2Cu. The Cu-Y coordination number is 1.1 +/- 0.2, and the Cu-Y distance is similar to 4% shorter than the sum of atomic radii, suggesting that attraction between Cu and Y plays an important role in stabilizing the glassy state. Thermal stability and structure evolution upon annealing were also studied by differential scanning calorimetry and in situ x-ray powder diffraction. The alloy shows a glass transition and three crystallization events, the first and dominant one at 456 K corresponding to eutectic crystallization of at least three phases: Mg2Cu and most likely cubic MgY and CuMgY.

Short range order of amorphous Mg60Cu30Y10 was investigated by x-ray and neutron diffraction, Cu and Y K-edge x-ray absorption fine structure measurements, and the reverse Monte Carlo simulation technique. We found that Mg-Mg and Mg-Cu nearest neighbor distances are very similar to values found in crystalline Mg2Cu. The Cu-Y coordination number is 1.1 +/- 0.2, and the Cu-Y distance is similar to 4% shorter than the sum of atomic radii, suggesting that attraction between Cu and Y plays an important role in stabilizing the glassy state. Thermal stability and structure evolution upon annealing were also studied by differential scanning calorimetry and in situ x-ray powder diffraction. The alloy shows a glass transition and three crystallization events, the first and dominant one at 456 K corresponding to eutectic crystallization of at least three phases: Mg2Cu and most likely cubic MgY and CuMgY.

Research in the department covers the field of condensed matter physics. The principal activities of the department are presented in this Progress Report covering the period from 1 January to 31 December 1991. The condenses matter physics research is predominantly experimental utilising diffraction of neutrons and X-rays. The research topics range from studies of two- and threedimensional structures, magnetic ordering, heavy fermions, high Tc superconductivity, phase transitions in model systems to studies of precipitation phenomena and nano-scale structures m various materials. The major interest of the department is in basic research, but projects of more applied nature are often taken up, prompted by the applicability of the developed technique and expertise.

Research in the Physics Department covers the field of condensed matter physics. The principal activities of the department are presented in this Progress Report covering the period from 1 January to 31 December 1990. The condensed matter physics research is predominantly experimental utilising diffraction of neutrons and X-rays. The research topics range from studies of two- and threedimensional structures, magnetic ordering, heavy fermions, phase transitions in model systems to studies of texture and recrystallization kinetics and with a more applied nature. The discovery of the high Tc superconductors in 1986 has opened an important new research area, where neutron and X-ray diffraction are used to elucidate the basic mechanism responsible for the superconductivity and in the analysis of the solid stale syntheses used when producing the materials.

Research in the Physics Department covers two main fields: condensed matter physics and plasma physics. The principal activities in these fields are presented in this Progress Report covering the period from 1 January to 31 December 1989. The condensed matter physics research is predominantly experimental utilising diffraction of neutrons and x-rays. The research topics range from studies of two-and three-dimensional structures, magnetic ordering, heavy fermions, phase transitions in model systems to studies of texture and recrystallization kinetics with a more applied nature. The discovery of the high Tc superconductors in 1986 has opened an important new research area, where neutron and x-ray diffraction are used to elucidate the basic mechanism responsible for the superconductivity and in the analysis of the solid state syntheses used in producing the materials. The plasma physics research is partly experimental and partly theoretical. The plasma physics programme is also of a wide scope ranging from fundamental studies of wave propagation, instabilities, solitons and turbulence in plasmas to refuelling a fusion reactor by deuterium-tritium pellets.