Appearance of Successive Phase Transition in SmRu4P12 under High Magnetic Fields Probed by 31P Nuclear Magnetic Resonance

TL;DR

This study uses 31P-NMR to investigate the magnetic and electronic phase transitions in SmRu4P12 under high magnetic fields, revealing complex magnetic structures and phase behavior associated with the metal-insulator transition.

Contribution

It provides new insights into the field-induced successive phase transitions in SmRu4P12 through detailed NMR measurements, highlighting the emergence of internal magnetic fields and complex spectral structures.

Findings

Rapid increase in NMR line width below TMI indicating internal fields

Complex spectral structures observed between TN and TMI at high fields

Strong suppression of 1/T1 between TN and TMI above 70 kOe

Abstract

The 31P-NMR (nuclear magnetic resonance) measurements of the filled skutterudite SmRu4P12 have been carried out in several applied magnetic fields. The line width of the 31P-NMR spectrum rapidly increases below the metal-insulator transition temperature TMI, which indicates the appearance of an internal field below the temperature. Though no distinct anomaly was observed below TMI in low fields, a complicated structure was observed between the Neel temperature TN and TMI (TN < TMI) above 70 kOe. The spin-lattice relaxation rate 1/T1 is almost independent of temperature above TMI, and rapidly decreases below TMI. The 1/T1 in low fields decreases monotonously, whereas the strong suppression of 1/T1 occurs between TN and TMI above 70 kOe. The structure of the spectra and the suppression of 1/T1 become apparent with increasing field.