Measuring nanoscale magnetic write head fields using a hybrid quantum register

TL;DR

This paper demonstrates a method to measure and control nanoscale magnetic fields using quantum spins, enabling high-resolution, high-bandwidth magnetic field profiling crucial for advancing magnetic device miniaturization.

Contribution

It introduces a hybrid quantum register approach to characterize nanoscale magnetic fields with arbitrary orientation and high spatial and temporal resolution.

Findings

Achieved magnetic field profiling with gradients up to 10 mT/nm.

Measured static and dynamic magnetic fields in all orientations.

Demonstrated GHz-range coherent control of single spins.

Abstract

The generation and control of nanoscale magnetic fields are of fundamental interest in material science and a wide range of applications. Nanoscale magnetic resonance imaging quantum spintronics for example require single spin control with high precision and nanoscale spatial resolution using fast switchable magnetic fields with large gradients. Yet, characterizing those fields on nanometer length scales at high band width with arbitrary orientation has not been possible so far. Here we demonstrate single electron and nuclear spin coherent control using the magnetic field of a hard disc drive write head. We use single electron spins for measuring fields with high spatial resolution and single nuclear spins for large band width measurements. We are able to derive field profiles from coherent spin Rabi oscillations close to GHz in fields with gradients of up to 10 mT/nm and measure all components of a static and dynamic magnetic field independent of its orientation. Our method paves the way for precision measurement of the magnetic fields of nanoscale write heads important for future miniaturization of the devices.