Separation of bulk and surface contributions to the damping of permalloy on large-area chemical-vapor-deposited <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mrow> <mml:mi>Mo</mml:mi> <mml:mi mathvariant="

The ability to develop practical spintronic devices that use 2D van der Waals materials requires research on wafer-scale materials typically fabricated using chemical vapor deposition (CVD). In this report, we investigate spin pumping effects using ferromagnetic resonance spectroscopy (FMR) in wafer-scale transition-metal dichalcogenide–ferromagnetic (FM) heterostructures, specifically, <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msub> <a:mrow> <a:mi>Mo</a:mi> <a:mi mathvariant="normal">S</a:mi> </a:mrow> <a:mn>2</a:mn> </a:msub> </a:math> - <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"> <d:msub> <d:mi>Ni</d:mi> <d:mrow> <d:mn>0.8</d:mn> </d:mrow> </d:msub> <d:msub> <d:mi>Fe</d:mi> <d:mrow> <d:mn>0.2</d:mn> </d:mrow> </d:msub> </d:math> bilayers with varying <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"> <f:msub> <f:mi>Ni</f:mi> <f:mrow> <f:mn>0.8</f:mn> </f:mrow> </f:msub> <f:msub> <f:mi>Fe</f:mi> <f:mrow> <f:mn>0.2</f:mn> </f:mrow> </f:msub> </f:math> thicknesses. The FMR measurements allow the phenomenological damping parameter <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"> <h:mi>α</h:mi> </h:math> of the FM layer to be determined, with increased values often attributed to injection of spins across an interface through spin pumping. Our results on sputtered <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"> <j:msub> <j:mi>Ni</j:mi> <j:mrow> <j:mn>0.8</j:mn> </j:mrow> </j:msub> <j:msub> <j:mi>Fe</j:mi> <j:mrow> <j:mn>0.2</j:mn> </j:mrow> </j:msub> <j:mo stretchy="false">(</j:mo> <j:mi>t</j:mi> <j:mo stretchy="false">)</j:mo> </j:math> films deposited on monolayer and bilayer CVD-grown <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"> <n:mrow> <n:mi>Mo</n:mi> <n:mi mathvariant="normal">S</n:mi> </n:mrow> </n:math> <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"> <q:msub> <q:mi/> <q:mn>2</q:mn> </q:msub> </q:math> show a lower contribution to <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"> <s:mi>α</s:mi> </s:math> from surface effects than a film of the same thickness deposited on <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"> <u:mrow> <u:mi>Si</u:mi> <u:mi mathvariant="normal">O</u:mi> </u:mrow> </u:math> <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"> <x:msub> <x:mi/> <x:mn>2</x:mn> </x:msub> </x:math> . A reduction in surface damping is often attributed to a drop in spin pumping, but this work demonstrates that other interfacial effects such as spin-memory loss must also be considered in determining the physical origin of the measured damping parameter.