magnetostrictive delay line
An early storage device that used tensioned wires of nickel alloy carrying longitudinal waves produced and detected electromagnetically.
They had better storage behaviour than mercury delay lines.
[H. Epstein and O.B. Stram, "A High Performance Magnetostriction-Sonic Delay Line," Transactions, Institute of Radio Engineers, Professional Group on Ultrasonic Engineering, 1957, pp. 1-24].