  We integrate a long-lived memory qubit into a mixed-species trapped-ion
quantum network node. Ion-photon entanglement first generated with a network
qubit in Sr-88 is transferred to Ca-43 with 0.977(7) fidelity, and mapped to a
robust memory qubit. We then entangle the network qubit with a second photon,
without affecting the memory qubit. We perform quantum state tomography to show
that the fidelity of ion-photon entanglement decays ~70 times slower on the
memory qubit. Dynamical decoupling further extends the storage duration; we
measure an ion-photon entanglement fidelity of 0.81(4) after 10s.
