Existence of Fine Structure inside Spin Gap in CeRu2Al10

TL;DR

This study explores the magnetic field effects on the spin gap in CeRu2Al10, revealing complex magnetic phases and fine structures within the spin gap through magnetization and resistivity measurements.

Contribution

It provides new evidence of fine structures within the spin gap of CeRu2Al10, supported by detailed magnetic and transport measurements under varying magnetic fields.

Findings

Metamagnetic-like anomaly at H*~4 T for H//c

Suppression of resistivity shoulder at Ts~5 K by magnetic field

Multiple magnetic phases below T_0=27 K

Abstract

We investigate the magnetic field effect on the spin gap state in CeRu2Al10 by measuring the magnetization and electrical resistivity. We found that the magnetization curve for the magnetic field H//c shows a metamagnetic-like anomaly at H*~4 T below T_0=27 K, but no anomaly for H//a and H//b. A shoulder of the electrical resistivity at Ts~5 K for I//c is suppressed by applying a longitudinal magnetic field above 5 T. Many anomalies are also found in the magnetoresistance for Hkc below ~5 K. The obtained magnetic phase diagram consists of at least two or three phases below T_0. These results strongly indicate the existence of a fine structure at a low energy side in a spin gap state with the excitation energy of 8 meV recently observed in the inelastic neutron scattering experiments.