Large Anomalous Nernst Effect in Disordered CoPt Thin Films for Planar Thermoelectric Sensing

The anomalous Nernst effect ( ANE ), which converts a thermal gradient into a transverse electric field, offers a promising route for planar thermoelectric devices and microscale heat‐flux sensors. In this study, we systematically investigated the compositional dependence of ANE and thermal transport in Co 1 − x Pt x thin films deposited on quartz glass substrates using DC magnetron co‐sputtering. A strong compositional dependence of the transverse thermopower ( S ANE ) was observed, showing a significant tenfold enhancement from 0.33 µV K − 1 to 3.22 µV K − 1 . The corresponding transverse thermoelectric constant ( α xy ) reached 5 A m − 1 K − 1 , closely following an intrinsic‐like scaling behavior with anomalous Hall conductivity ( σ xy ). By tuning the Pt concentration, we achieved a notable ratio in the | α xy |/| σ xy | close to the well‐known k B /e benchmark observed in topological magnets. The ANE sensitivity ( E / J Q ) exhibited a maximum of 0.3 µm A − 1 at x = 50%, accompanied by a reduced thermal conductivity of ≈10 W m − 1 K − 1 . Our results demonstrate that disordered CoPt films can simultaneously achieve low κ and large intrinsic ANE response, highlighting that disordered or partially crystalline structures can sustain strong transverse thermoelectric transport and are promising candidates for high‐sensitivity thermoelectric and heat‐flux sensing applications.