Successive magnetic transitions of Ca$_2$CoSi$_2$O$_7$ in high magnetic fields

TL;DR

This study investigates the magnetic and dielectric properties of Ca$_2$CoSi$_2$O$_7$ single crystals under high magnetic fields, revealing multiple magnetic transitions, magnetization plateaus, and magnetoelectric effects linked to spin system changes.

Contribution

It provides the first detailed analysis of magnetic transitions and magnetoelectric effects in Ca$_2$CoSi$_2$O$_7$ under pulsed high magnetic fields, highlighting symmetry-breaking phenomena.

Findings

Observation of a magnetization plateau below saturation.

Detection of multiple anomalies indicating symmetry breaking.

Measurement of quadratic magnetoelectric tensor consistent with orthorhombic symmetry.

Abstract

Magnetic and dielectric properties of \aa kermanite Ca$_2$CoSi$_2$O$_7$ single crystals were investigated in pulsed high magnetic fields. In magnetic fields along the $c$ axis, this material shows a magnetization plateau in a wide range of field below the saturation. Magnetization processes for fields along the $a$ and $b$ axes show multiple anomalies but different traces to each other, indicating the breaking of four-fold symmetry. Measurements of the magnetoelectric effects exhibit the changes in electric polarization according to the changes in the spin system. The experimentally determined quadratic magnetoelectric tensor is consistent with that expected in the crystal symmetry of orthorhombic $P2_12_12$.