Zero field NMR
Zero- to ultralow-field (ZULF) NMR is the acquisition of nuclear magnetic resonance (NMR) spectra of chemicals with magnetically active nuclei (spins 1/2 and greater) in an environment carefully screened from magnetic fields (including from the Earth's field). ZULF NMR experiments typically involve the use of passive or active shielding to attenuate Earth's magnetic field.