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Solid-state battery technology is motivated by the desire to deliver flexible power storage in a safe and efficient manner. The increasingly widespread use of batteries from mass production facilities highlights the need for a rapid and sensitive diagnostic tool for identifying battery defects. We demonstrate the use of atomic magnetometry to measure the magnetic fields around miniature solid-state battery cells. These fields encode information about battery manufacturing defects, state of charge, and impurities, and they can provide important insights into battery aging processes. Compared with SQUID-based magnetometry, the availability of atomic magnetometers, however, highlights the possibility of constructing a low-cost, portable, and flexible implementation of battery quality control and characterization technology. 

The emergence of spin‐orbit torques as a promising approach to energy‐efficient magnetic switching has generated large interest in material systems with easily and fully tunable spin‐orbit torques. Here, current‐induced spin‐orbit torques in VO₂/NiFe heterostructures are investigated using spin‐torque ferromagnetic resonance, where the VO₂layer undergoes a prominent insulator‐metal transition. A roughly twofold increase in the Gilbert damping parameter, α, with temperature is attributed to the change in the VO₂/NiFe interface spin absorption across the VO₂phase transition. More remarkably, a large modulation (±100%) and a sign change of the current‐induced spin‐orbit torque across the VO₂phase transition suggest two competing spin‐orbit torque generating mechanisms. The bulk spin Hall effect in metallic VO₂, corroborated by the first‐principles calculation of the spin Hall conductivity , is verified as the main source of the spin‐orbit torque in the metallic phase. The self‐induced/anomalous torque in NiFe, with opposite sign and a similar magnitude to the bulk spin Hall effect in metallic VO₂, can be the other competing mechanism that dominates as temperature decreases. For applications, the strong tunability of the torque strength and direction opens a new route to tailor spin‐orbit torques of materials that undergo phase transitions for new device functionalities.