Simulation and measurement of stray fields for the manipulation of spin-qubits in one- and two-dimensional arrays

Understand

The inhomogeneous magnetic stray field of micromagnets has been extensively used to manipulate electron spin qubits.

• By means of micromagnetic simulations and scanning superconducting quantum interference device microscopy, we show that the polycrystallinity of the magnet and non-uniform magnetization significantly impact the stray field and corresponding qubit properties.
• We find that the random orientation of the crystal axis in polycrystalline Co magnets alters the qubit frequencies by up to 0.5 GHz, compromising single qubit addressability and single gate fidelities.
• We map the stray field of Fe micromagnets with an applied magnetic field of up to 500 mT (mimicking conditions when operating qubits), finding field gradients above 1 mT/nm.