Nuclear magnetic resonance (NMR) experiments under extreme conditions are often limited by very small sample volumes available in high-pressure devices. Recent advances in magnetic flux tailoring and micro-resonator design have extended inductive NMR detection to picoliter-scale samples while preserving spectral resolution and quantitative accuracy. These developments enable a broader range of NMR experiments directly on the microscopic samples inherent to high-pressure research.

In this contribution we introduce three complementary experimental approaches that together establish a unified micro-scale NMR toolbox for in-situ high-pressure studies. Each technique probes different physical observables while relying on the same underlying micro-resonator architecture.

The first approach, μΩ-NMR, provides high-resolution spectroscopy of microscopic samples. Using Lee–Goldburg decoupling together with the large RF field amplitudes available in micro-resonators, dipolar interactions can be efficiently averaged, yielding spectral resolutions approaching 0.1 ppm, allowing for structural analysis at mega-bar pressures

The second method, μQ-NMR, exploits the quantitative nature of NMR signal intensities together with the strong increase in mass sensitivity of RF resonators as their volume decreases. This approach enables detection and quantification of trace elements at ppb-level concentrations in microscopic samples.

The third technique, μT²-NMR, is a micro-scale correlation relaxometry method designed to probe collective spin dynamics. By observing the evolution of transverse spin correlations and long-time dipolar response, this approach provides insight into many-body spin interactions and microscopic dynamical processes that are otherwise difficult to access in confined samples.

Together, these three approaches establish a trifecta of complementary measurement capabilities—spectral structure, spin dynamics, and quantitative composition—within a single experimental platform. This framework significantly expands the range of NMR experiments that can be performed on microscopic samples and provides new opportunities for studying materials and planetary minerals under extreme pressure conditions.