An emergence of chiral helimagnetism or ferromagnetism governed by Cr intercalation in a dichalcogenide CrNb$_{3}$S$_{6}$

TL;DR

This study explores how varying Cr intercalation levels in Cr$_x$Nb$_3$S$_6$ crystals influences their magnetic properties, revealing that precise Cr content is crucial for observing chiral magnetic soliton lattice behavior at high transition temperatures.

Contribution

It systematically demonstrates the impact of Cr intercalation on magnetic properties and the formation of chiral magnetic soliton lattices in Cr$_x$Nb$_3$S$_6$ single crystals, highlighting synthesis control.

Findings

Cr intercalation level critically affects magnetic transition temperature.

Chiral magnetic soliton lattice observed only within narrow Cr concentration range.

Highest $T_c$ of 133 K achieved at specific Cr contents.

Abstract

A synthesis of single crystals of chiral dichalcogenides $TM_{3}X_{6}$ ($T$: 3$d$ transition metal, $M$: Nb or Ta, $X$: S or Se) remains an intriguing issue for the investigation of emergent quantum properties such as chiral helimagnetism. In this study, we investigated a correlation between the quantity of Cr intercalation $x$ and magnetic property in single crystals of a chromium (Cr) intercalated chiral disulfide Cr$_x$Nb$_3$S$_6$ in order to optimize the synthesis condition for the intercalation-controlled single crystals. The magnetic properties including a magnetic transition temperature $T_{c}$ take different values depending on the samples. We systematically grew single crystals of Cr$_{x}$Nb$_{3}$S$_{6}$ with $x$ ranged from 0.89 to 1.03 and found that the amount of the Cr intercalation $x$ is an essential factor in controlling the magnetic properties of the grown crystals. The magnetization anomaly, which appears in the temperature dependence as evidence of the formation of chiral magnetic soliton lattice (CSL), was observed only in a narrow region of $x$ from 0.98 to 1.03. The single crystals with $x$ being 0.98 and 0.99 showed the CSL behavior with the highest $T_{c}$ of 133 K. These results indicate that small amount of defects on the sites for $T$ ions dramatically affects the quality of the single crystals in the synthesis of $TM_{3}$S$_{6}$. We also discuss an importance of synthesizing enantiopure single crystals of chiral dichalgogenides in order to observe chiral physical properties unique to chiral compounds such as magneto-chiral effect and chiral-induced spin selectivity.