Magnetoresistance of Al90Y10 and Al90La10: Strong enhancement due to small crystalline precipitates in Al90La10.

The normal-state magnetoresistance, \ensuremath{\Delta}\ensuremath{\rho}/\ensuremath{\rho}, was measured for ${\mathrm{Al}}_{90}$${\mathrm{La}}_{10}$ and ${\mathrm{Al}}_{90}$${\mathrm{Y}}_{10}$ alloys in the temperature region from four to eight times the superconducting ${\mathit{T}}_{\mathit{c}}$ and in magnetic fields up to 12 T. These samples were amorphous in standard x-ray diffraction. An accurate description of the ${\mathrm{Al}}_{90}$${\mathrm{Y}}_{10}$ data in terms of quantum interference effects (QIE) was obtained only when the Maki-Thompson contribution was excluded. Two samples of ${\mathrm{Al}}_{90}$${\mathrm{La}}_{10}$ were studied. \ensuremath{\Delta}\ensuremath{\rho}/\ensuremath{\rho} was anomalously enhanced in sample I, reaching above 1%, and too large to be accounted for by QIE also in sample II. Measurements of the magnetic susceptibility and further structural investigations were made, including high-resolution x-ray diffraction, analytical transmission electron microscopy, and high-resolution electron microscopy (HREM). Small crystallites of ${\mathrm{Al}}_{11}$${\mathrm{La}}_{3}$ were observed in all improved structural analyses of sample I, and only in HREM for sample II. Implications for amorphous metals are discussed. \textcopyright{} 1996 The American Physical Society.