Are database backups specific to the OS on which they are created?
In Oracle, you can restore onto an OS/CPU with the same endianness in most cases. This can be done with RMAN, the standard Oracle backup and restore tool, but it might be worth it to  investigate options such as DataPump or a Linux VM on AIX (but I don't know how that would deal with endianness). x86 is little-endian and POWER is big-endian, so this would not necessarily be straightforward.