Magnetization and Magnetoresistance of CeRu2Al10 under High Magnetic Fields along c-Axis

TL;DR

This study investigates the magnetic and electronic properties of CeRu2Al10 under high magnetic fields, revealing complex antiferromagnetic order and Fermi surface characteristics through magnetization and magnetoresistance measurements.

Contribution

It provides the first direct evidence of the Fermi surface below T0 and explores the anisotropic magnetic behavior in CeRu2Al10 under high magnetic fields.

Findings

Magnetization increases linearly with field along c-axis with a small slope.

No phase transition anomaly observed in magnetoresistance below 4.2 K.

Fermi surface cross section estimated at 1.0×10^14 cm^-2 from Shubnikov-de Haas oscillations.

Abstract

We have studied the magnetization and magnetoresistance of CeRu2Al10 in the applied magnetic field H along the c-axis up to ~ 55 T. The magnetization M at low temperatures shows an H-linear increase with a small slope of M/H than that for H // a-axis up to ~ 55 T after showing a small anomaly at H ~ 4 T, which indicates that the critical field to the paramagnetic phase H_c^p is higher than 55 T for H // c-axis. The magnetization curves for H // a- and c-axes below the antiferro magnetic (AFM) transition temperature T0 behave as if the magnetic anisotropy in the AFM-ordered phase is small, although there exists a large magnetic anisotropy in the paramagnetic phase, which favors the easy magnetization axis along the a-axis. On the other hand, very recently, Khalyavin et al. have reported that the AFM order where the magnetic moment is parallel to the c-axis takes place below T0. These results indicate that the AFM order in this compound is not a simple one. The longitudinal magnetoresistance for H // c-axis at low temperatures shows no anomaly originating from the phase transition, but shows oscillations below 4.2 K. This oscillatory behavior below 4.2 K originates from the Shubnikov-de Haas oscillations, from which the cross section of the Fermi surface normal to the c-axis is estimated to be 1.0*10^14 cm-2, with no large effective mass. This is the first direct evidence of the existence of the Fermi surface below T0.