A 4Kbit bubble memory chip using X-bar propagation patterns

The design and operation margins of a bubble memory chip 2,8 mm × 2,1 mm with 32 minor loops of 128 bits of storage capacity each are described. In a special package, designed for test purposes and containing the drive field coils and a variable bias magnet system, signals up to 10 mV are generated by bubbles of 6 μm diameter in a thin film detector. The X-bar propagation works well up to 500 kHz using garnets having the composition Y
1,6
Sm
0,4
Ca
1
Fe
3,9
Ge
1
Si
0,1
O
12
. Also the transfer is performed by special X-bar transfer gates.