In comparison to highhyphen;field NMR, zerohyphen;field techniques offer advantages in terms of spectral interpretability in studies of polycrystalline or amorphous solids. This article describes a technique and apparatus for timehyphen;domain measurements of nuclear magnetism in the absence of applied fields (Fourier transform zerohyphen;field NMR and NQR). Magnetic field cycling and high field detection are employed to enhance sensitivity. The field cycling is accomplished with an airhyphen;driven shuttle system which moves the sample between regions of high and low magnetic field, in combination with switchable electromagnets in the lowhyphen;field region. Sudden field steps or pulses are used to initiate coherent nuclear spin evolution in zero field and to monitor such evolution as a function of time. Experimental results are shown and analyzed. Possible variations on the basic method are described and their relative advantages are discussed.
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