$^{27}$Al NMR Measurements of YMn$_4$Al$_8$

We have performed $^{27}$Al nuclear magnetic resonance (NMR) measurements on the single crystals of YMn$_4$Al$_3$. $^{27}$Al NMR spectrum, Knight shift, spin-lattice and transverse relaxation rates, $1/T_1$ and $1/T_2$, were measured down to 4 K at 8 T. Experimental results of the Knight shift and the nuclear spin lattice relaxation rate as well as magneto-resistance and susceptibility are analyzed and discussed in conjunction with the pseudogap behavior in the spin excitation spectrum.