Nuclear magnetic resonance in icosahedral Al-Pd-Mn alloys

²⁷Al and⁵⁵Mn nuclear magnetic resonance shift,K, and²⁷Al spin lattice relaxation time,T ₁, have been measured for the six-dimensional face-centered icosahedral quasicrystals, Al_75-x Pd₁₅Mn_10+x withx=0, 2 and7. The Al₇₅Pd₁₅Mn₁₀ quasicrystal exhibits a temperature independent Knight shiftK and(T ₁ T)^–1=0.022±0.002 (K s)^–1 in a temperature range from room temperature to 5 K because there exist no Mn atoms with local magnetic moment. The replacement of Al with Mn drastically decreases the²⁷AlK, the⁵⁵MnK andT ₁ of²⁷Al, andthe²⁷AlK becomes negative. There is an additional contribution to the spin lattice relaxation time independent of temperature. This is considered to be due to the presence of a localized magnetic moment in the replaced Mn atoms.