Is memory possible without a flip flop circuit?
Flash memory stores bits in an isolated conductor within a floating gate transistor, with no feedback required to maintain the state.

DRAM stores data in the charge state of a capacitor, however the data will be lost over time due to leakage currents.

Core memory can store a bit in the magnetic state of a magnetic material. Feedback isn't required to maintain the state, but it can only be read once before the state is disturbed.

Fuses can be used to store information by simply overheating and destroying a small wire (or not). The state is maintained without feedback. However, they can only be written once.