Magnetic field-Temperature Phase Diagram of CeCoSi Constructed by Specific Heat, Magnetoresistivity, and Magnetization Measurements for a Single Crystal

TL;DR

This study maps the magnetic field-temperature phase diagram of CeCoSi single crystals using specific heat, magnetoresistivity, and magnetization measurements, revealing field-induced regions and electronic state changes.

Contribution

It provides detailed phase diagrams for CeCoSi under magnetic fields, highlighting new regions and electronic state transitions not previously characterized.

Findings

Sign change in magnetoresistivity at T_0 indicating electronic state change

Identification of B-induced regions in the magnetic phase diagrams

Observation of possible symmetry change or domain effects under magnetic fields

Abstract

A Ce-based metallic compound CeCoSi with a tetragonal structure exhibits successive phase transitions: the one whose order parameter is unidentified at T_0 = 12 K and the antiferromagnetic one at T_N = 9.4 K. We performed specific heat, magnetoresistivity (MR), and magnetization measurements for a single crystal CeCoSi at low temperatures in magnetic fields B of up to 14 T and constructed detailed magnetic field--temperature phase diagrams for both B || [100] and [001]. The longitudinal MR measured for B || [100] shows a sign change from negative to positive across T_0 = 13 K updated in the present sample, indicating a clear change in an electronic state. In addition, the constructed magnetic phase diagrams for both the field directions have a B-induced region in each ordered state. The presence of the newly found regions would be attributed to a change in the symmetry of the order parameter or domain alignment by applying B.