NMR relaxometry is an analytical technique that provides information about the molecular environment by analyzing the properties of NMR signals versus the magnitude of the longitudinal field. In this work, we present NMR relaxometry at zero and ultra-low magnetic fields (ZULFs). Operation under ZULFs allows us to investigate many slow (bio)chemical processes, whose timescale (milliseconds-seconds) coincides with a timescale of spin evolution. In contrast to their high-field NMR, ZULF NMR measurements can be performed with atomic magnetometers. Here, we share the dataset obtained from ZULF NMR relaxometry measurements of (bio)chemical compounds containing 1H 13C, 1H-15N, and 1H-31P spin pairs, human whole-blood and blood-plasma.

ZULF NMR signals arising from various (bio)chemical compounds, human whole-blood and blood-plasma were detected using atomic magnetometers. This dataset consists of raw ZULF NMR data.