Comparative study of the structural and magnetic properties of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">Mn</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">NbS</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">Cr</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">NbS</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
A. E. Hall, J. C. Loudon, Paul A. Midgley, A. C. Twitchett-Harrison, Samuel Holt, D. A. Mayoh, J.P. Tidey, Yisong Han, M. R. Lees, G. Balakrishnan
Abstract
We compare the magnetism of single crystals of the intercalated transition metal dichalcogenides ${\mathrm{Cr}}_{1/3}\mathrm{Nb}{\mathrm{S}}_{2}$ and ${\mathrm{Mn}}_{1/3}\mathrm{Nb}{\mathrm{S}}_{2}$ using techniques such as dc and ac susceptibility and Lorentz transmission electron microscopy (LTEM). We present a detailed structural investigation of these materials using electron and single-crystal x-ray diffraction measurements to show how substitutional disorder and stacking faults can manifest in ${\mathrm{Cr}}_{1/3}\mathrm{Nb}{\mathrm{S}}_{2}$ and ${\mathrm{Mn}}_{1/3}\mathrm{Nb}{\mathrm{S}}_{2}$, and give rise to additional superlattice reflections in diffraction patterns acquired from ${\mathrm{Mn}}_{1/3}\mathrm{Nb}{\mathrm{S}}_{2}$. Magnetic susceptibility and LTEM measurements show ${\mathrm{Cr}}_{1/3}\mathrm{Nb}{\mathrm{S}}_{2}$ displays chiral helimagnetism below its magnetic ordering temperature (${T}_{\mathrm{C}}$) of 111 K, while there is no evidence that ${\mathrm{Mn}}_{1/3}\mathrm{Nb}{\mathrm{S}}_{2}$ exhibits helimagnetic ordering below its transition temperature ${T}_{\mathrm{C}}=45$ K.