Magnetic and Transport Properties of (La,Sr)MnO3_3

Magnetic and transport properties of the perovskite-type $3d$ transition-metal oxide (La,Sr)MnO$_3$ are theoretically studied using the double-exchange model in infinite dimension. Magnetoresistance properties as well as the magnetic transition temperatures are in good agreement with the experimental data.Comment: 5 pages, LaTeX, including 2 PS figures. To be published in Proc. International Symposium 'Frontiers of High Tc Superconductivity' (Oct. 1995, Morioka, Japan

Magnon Broadening Effects in Double Layered Manganite La_1.2 Sr_1.8 Mn_2 O_7

Magnon linewidth of La_1.2 Sr_1.8 Mn_2 O_7 near the Brillouin zone boundary is investigated from both theoretical and experimental points of view. Abrupt magnon broadening is ascribed to a strong magnon-phonon coupling. Magnon broadening observed in cubic perovskite manganites is also discussed.Comment: 4 pages + 1 jpeg figur

Review of NMR studies of nanoscale molecular magnets composed of geometrically frustrated antiferromagnetic triangles

We present a comprehensive review of nuclear magnetic resonance (NMR) studies performed on three nanoscale molecular magnets with different configurations of geometrically frustrated antiferromagnetic (AFM) triangles, new spin frustration systems with different novel structures: (1) the isolated single AFM triangle K$_6$[V$_{15}$As$_6$O$_{42}$(H$_2$O)]$\cdot$8H$_2$O (in short V15), (2) the spin ball [Mo$_{72}$Fe$_{30}$O$_{252}$(Mo$_2$O$_7$(H$_2$O))$_2$ (Mo$_2$O$_8$H$_2$(H$_2$O))(CH$_3$COO)$_{12}$(H$_2$O)$_{91}$]$\cdot$150H$_2$O (in short Fe30 spin ball), and (3) the twisted triangular spin tube [(CuCl$_2$tachH)$_3$Cl]Cl$_2$ (in short Cu3 spin tube).Comment: 13 pages, 14 figure