Optimizing magnetic dopants in ferroelectrics for defect-based qubits

Introducing magnetic dopants to ferroelectric crystals provides unpaired spins with coupled electrical and magnetic properties that could be utilized in a novel spin-oxide qubit platform. Depending on the symmetry of the ferroelectric host, the spins preferentially align relative to the polar axis and follow manipulation of the polar axis by an applied electric field. We demonstrate this electric-field control by a combined first-principles and electron paramagnetic resonance study of the model system Fe³⁺-doped PbTiO₃. We further explore ferroelectric oxide systems with reduced symmetry, alternative dopants and lattice modifications to optimize the magnetoelectric coupling and understand spin-lattice decoherence channels. These results demonstrate the manipulation of spins by an electric field and the options available for optimizing spin control by tailoring the atomic environment.