Design of a 1.5-Million-Bit Plated-Wire Memory

Abstract

A complete feasibility model is now being utilized to demonstrate the design of this miniature space-borne memory. A continuous layer 10 000 Å thick of nonmagnetostrictive Ni-Fe alloy, plated on 5-mil-diam Be-Cu wire, is the memory element. No significant changes were measured in operating current margins of two 768-bit memory systems. Each was continuously operated for 1000 h at 75°–80°C. The magnetic properties are stable for the transverse drive duty factors tested which were less than 100%. More than 1000 h in a 95°C and 85% relative humidity atmosphere show that a clean, uncoated surface is nearly free of corrosion. The few tiny points that form seem to be self-limiting after 100 h. A temperature coefficient of −0.06%/°C on the transverse drive current results in a constant output signal from −55°C to +80°C. The transverse field drive line is a composite Cu-plated Ni-Fe alloy structure. This makes possible lower drive current and higher bit packing density. The 1.5×106 bit momory stack, with 2300 diodes, is designed to fit in 6×2.4×13 in. (187 in.3) including the case. The entire memory system consisting of two independent 1.4×106 bit memories consumes 1.5 W operating at a 500-kc/sec bit rate.

Phase Change Memory: From Devices to Systems

“…Notable among them are the use of magnetic bubbles or domains for data storage (bubble memory [62]), use of magnetostriction for moving domain walls (twister memory [20]) and electroplating nickel-iron permalloy on wires (plated wire memory [43]). Notable among them are the use of magnetic bubbles or domains for data storage (bubble memory [62]), use of magnetostriction for moving domain walls (twister memory [20]) and electroplating nickel-iron permalloy on wires (plated wire memory [43]).…”