Ground-state magnetic structures of topological kagome metals <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>R</mml:mi><mml:msub><mml:mi mathvariant="normal">V</mml:mi><mml:mn>6</mml:mn></mml:msub><mml:msub><mml:mi>Sn</mml

Magnetic kagome metals have attracted tremendous research interests recently, because they represent an ideal playground for exploring the fascinating interplay between their intrinsically inherited topologically nontrivial electron band structures, magnetism and electronic correlation effects, and the resultant novel electronic/magnetic states and emergent excitations. In this work, we report a comprehensive single-crystal neutron diffraction investigation of the ground-state magnetic structures of the recently discovered V-based topological kagome metals <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi>R</a:mi><a:msub><a:mi mathvariant="normal">V</a:mi><a:mn>6</a:mn></a:msub><a:msub><a:mi>Sn</a:mi><a:mn>6</a:mn></a:msub></a:mrow></a:math> ( = Tb, Dy, Ho, Er). Furthermore, the sample synthesis details and our systematic studies of crystal structure, low-temperature magnetic and thermodynamic properties of these compounds via various in-house characterization techniques are also reported. Our single-crystal neutron diffraction measurements confirm that the long-range magnetic order forms below 4.3 K for <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mi>R</c:mi><c:mo>=</c:mo><c:mi>Tb</c:mi></c:mrow></c:math>, 3.0 K for <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mrow><d:mi>R</d:mi><d:mo>=</d:mo><d:mi>Dy</d:mi></d:mrow></d:math>, 2.4 K for <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mrow><e:mi>R</e:mi><e:mo>=</e:mo><e:mi>Ho</e:mi></e:mrow></e:math>, and 0.6 K for <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:mi>R</f:mi><f:mo>=</f:mo><f:mi>Er</f:mi></f:mrow></f:math>, respectively. The ground-state magnetic structures of the studied compounds are comprehensively determined via the magnetic crystallography approaches. It can be revealed that <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mrow><g:mi>R</g:mi><g:msub><g:mi mathvariant="normal">V</g:mi><g:mn>6</g:mn></g:msub><g:msub><g:mi>Sn</g:mi><g:mn>6</g:mn></g:msub></g:mrow></g:math> (<i:math xmlns:i="http://www.w3.org/1998/Math/MathML"><i:mi>R</i:mi></i:math> = Tb, Dy, Ho) have a collinear ferromagnetic order in the ground state, with the ordered magnetic moment aligned along the <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"><j:mi>c</j:mi></j:math> axis for <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"><k:mi>R</k:mi></k:math> = Tb, Ho, while approximately <l:math xmlns:l="http://www.w3.org/1998/Math/MathML"><l:mrow><l:mn>20</l:mn><l:msup><l:mrow/><l:mo>∘</l:mo></l:msup></l:mrow></l:math> tilted off from the <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mi>c</m:mi></m:math> axis for <n:math xmlns:n="http://www.w3.org/1998/Math/MathML"><n:mi>R</n:mi></n:math> = Dy. In contrast, <o:math xmlns:o="http://www.w3.org/1998/Math/MathML"><o:mrow><o:msub><o:mi>ErV</o:mi><o:mn>6</o:mn></o:msub><o:msub><o:mi>Sn</o:mi><o:mn>6</o:mn></o:msub></o:mrow></o:math> shows an A-type antiferromagnetic structure with a magnetic propagation vector = (0, 0, 0.5), and with the ordered magnetic moment aligned in the <p:math xmlns:p="http://www.w3.org/1998/Math/MathML"><p:mrow><p:mi>a</p:mi><p:mi>b</p:mi></p:mrow></p:math> plane. The ordered magnetic moments are determined as 9.4(2) <q:math xmlns:q="http://www.w3.org/1998/Math/MathML"><q:msub><q:mi>µ</q:mi><q:mi>B</q:mi></q:msub></q:math>, 6.6(2) <r:math xmlns:r="http://www.w3.org/1998/Math/MathML"><r:msub><r:mi>µ</r:mi><r:mi>B</r:mi></r:msub></r:math>, 6.4(2) <s:math xmlns:s="http://www.w3.org/1998/Math/MathML"><s:msub><s:mi>µ</s:mi><s:mi>B</s:mi></s:msub></s:math>, and 6.1(2) <t:math xmlns:t="http://www.w3.org/1998/Math/MathML"><t:msub><t:mi>µ</t:mi><t:mi>B</t:mi></t:msub></t:math> for <u:math xmlns:u="http://www.w3.org/1998/Math/MathML"><u:mi>R</u:mi></u:math> = Tb, Dy, Ho, and Er, respectively. A comparison of the low-temperature magnetic structures for both the extensively investigated topological kagome metal series of <v:math xmlns:v="http://www.w3.org/1998/Math/MathML"><v:mrow><v:mi>R</v:mi><v:msub><v:mi mathvariant="normal">V</v:mi><v:mn>6</v:mn></v:msub><v:msub><v:mi>Sn</v:mi><v:mn>6</v:mn></v:msub></v:mrow></v:math> and <x:math xmlns:x="http://www.w3.org/1998/Math/MathML"><x:mrow><x:mi>R</x:mi><x:msub><x:mi>Mn</x:mi><x:mn>6</x:mn></x:msub><x:msub><x:mi>Sn</x:mi><x:mn>6</x:mn></x:msub></x:mrow></x:math> is given in detail. This allows to gain new insights into the complex magnetic interactions, diverse single-ion magnetic anisotropies and spin dynamics in these compounds. The reported ground-state magnetic structures in <y:math xmlns:y="http://www.w3.org/1998/Math/MathML"><y:mrow><y:mi>R</y:mi><y:msub><y:mi mathvariant="normal">V</y:mi><y:mn>6</y:mn></y:msub><y:msub><y:mi>Sn</y:mi><y:mn>6</y:mn></y:msub></y:mrow></y:math> (<ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML"><ab:mi>R</ab:mi></ab:math> = Tb, Dy, Ho, Er) can pave the way for further explorations of the possible interplay between magnetism and topologically nontrivial electron band structures in the magnetically ordered phase regime. Published by the American Physical Society 2024