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Magnetic domain structures of Nd(1/2)Sr(1/2)MnO3 were investigated by means of low-temperature Lorentz electron microscopy. On cooling, magnetic domain walls started to appear at 250 K, and they were oriented straight along the [100] and [110] directions. With a further decrease in temperature, the volume of each magnetic domain increased with discontinuous domain-wall jumps. A characteristic granular image was observed at around 140 K, near the charge-ordering transition temperature. We consider that this originated from ferromagnetic nanoclusters that appeared in the antiferromagnetic matrix.

AuBa 2 Ca 2 Cu 3 O 9 (Au-1223-Ba) and AuBa 2 Ca 3 Cu 4 O 11 (Au-1234-Ba), two high-T c superconductors, were synthesized by high-pressure/high-temperature at 6 GPa and 1250-1300 °C. These phases are the third and fourth members of the AuBa 2 Ca n-1 Cu n O 2n+3 series. The Au-1223-Ba and Au-1234-Ba phases crystallize in an orthorhombic primitive system with the lattice parameters a ) 3.8182(4) Å, b ) 3.8555(4) Å, and c ) 15.445(2) Å, and a ) 3.8266(3) Å, b ) 3.8505(3) Å, and c ) 18.494(1) Å, respectively. The Au-1234-Ba phase showed bulk superconductivity below 99 K. The superconducting transition of the as-grown Au-1223-Ba sample was very broad with a transition temperature of ≈30 K and with a small superconducting volume fraction. The volume fraction increased after the sample was postannealed at 300 °C in O 2 atmosphere.

Elemental analysis in an oxycarbonate superconductor ((Cu,N,C)Sr2CaCu2Oy) is conducted using transmission electron microscope-electron energy-loss spectroscopy with detector-gain correction. The gain correction enables highly sensitive elemental analysis and precise measurement of energy-loss near edge structures (ELNESs). It is found that carbon is included as a CO3 group, because the carbon K-edge in the oxycarbonate shows the same ELNES observed from CaCO3. Nitrogen ELNES is similar to that of Sr(NO3)2, so nitrogen is contained as a NO3 group. Although both CO3(2-) and NO3- have similar planar atomic arrangements, the nitrogen ELNES observed is different from that of carbon. EEL spectrum simulation based on DV-Xalpha method is used to interpret the difference.

An analytical electron microscope based on the scanning transmission electron microscope with wavelength dispersive x-ray spectroscopy (STEM-WDX) to realize highly sensitive elemental imaging especially for light elements has been developed. In this study, a large-solid-angle multi-capillary x-rays lens with a focal length of 5 mm, long-time data acquisition (e.g. longer than 26 h), and a drift-free system made it possible to visualize boron-dopant images in a Si substrate at a detection limit of 0.2 atomic percent.