Dipolar spin echoes in magnetic resonance force microscopy

Limits for extending the coherence lifetime in force detected NMR spectroscopy are explored using time suspension pulse sequences based on the "magic echo." Two micron-sized single crystals of KP F6 and (N H4) 2 S O4 were used for demonstration, where a typical experiment measured signals of ∼ 1014 spins from a ∼0.8 μm wide imaging slice. By studying the decay of the dipolar echo maximum it is demonstrated that spectral linewidths of 1.1 kHz collected from a 100 kHz wide frequency slice can be obtained, extending the coherence lifetime for both samples by an order of magnitude. © 2006 The American Physical Society.