In-situ measurement of magnetic field gradient in a magnetic shield by a spin-exchange relaxation-free magnetometer*
Fang Jian-Chenga), Wang Taoa)†, Zhang Hongb), Li Yanga), Cai Hong-Weia)
       
Spectra of SERF magnetometer with 30-Hz calibration magnetic field in the z direction, the sensitivity in the z direction is 40 fT/Hz1/2, and the probe noise in the most sensitive axis is 5 fT/Hz1/2.