OPM magnetorelaxometry in the presence of a DC bias field Aaron Jaufenthaler, Volkmar Schultze, Theo Scholtes, Christian B. Schmidt, Michael Handler, Ronny Stolz and Daniel Baumgarten EPJ Quantum Technol., 7 1 (2020) 12 Published online: 16 September 2020 DOI: 10.1140/epjqt/s40507-020-00087-3