Atomic frequency comb memory with spin-wave storage in¹⁵³Eu^{3 +}:Y₂SiO₅

153Eu3 +:Y2SiO5 is a very attractive candidate for a long-lived, multimode quantum memory due to the long spin coherence time (∼15 ms), the relatively large hyperfine splitting (100 MHz) and the narrow optical homogeneous linewidth (∼100 Hz). Here we show an atomic frequency comb memory with spin-wave storage in a promising material 153Eu3 +:Y2SiO5, reaching storage times slightly beyond 10 μs. We analyse the efficiency of the storage process and discuss ways of improving it. We also measure the inhomogeneous spin linewidth of 153Eu3 +:Y2SiO5, which we find to be 69 ± 3 kHz. These results represent a further step towards realizing a long-lived, multimode solid-state quantum memory.