Evaluation of (YBiCa)3(FeSi)5O12epitaxial films for extended temperature range ion-implanted 4µm-period bubble devices

We report the results of wide temperature range material characterization and propagation studies on ion-implanted and annealed (Y
1.9
Bi
0.5
Ca
0.6
0.6)(Fe
4.4
Si
0.6
)O
12
Effective uniaxial anisotropy field H
k
decreases by less than a factor of 1.5 in going from -60C to +140 C compared with a factor of 8 for typical Lu-Sm garnets. Coercivity is less than 0.50e at -60C, and decreases monotonically to 0.14 Oe at 140C. Bubble propagation studies with 4μm-period ion-implanted propagation patterns and 40 Oe, 100 kHz drive field show propagation on the best type of tracks from -130 to 160C, with a bias field operating range greater than 30 Oe.