Magnetic resonance of a small platinum particle using an integrated dc SQUID

Abstract

We report the detection of pulsed nuclear magnetic resonance in a single 50 μm particle of platinum metal at 4 K and in an applied field of 60 G. The flux from the precessing spins is detected directly by an integrated dc SQUID minisusceptometer. The device can operate in applied fields of up to 100 G without degradation of noise performance. The particle contains ≊10 15 spin-active nuclei while the signal intensity corresponds to flux from 2.5×1014 spins all located at the center of the pickup loop. This result represents a significant improvement in the sensitivity of NMR and may be useful in the characterization of materials with small spin populations.