Magnetic field induced modulation of heat transport in CrPS${}_4$ probed by TaIrTe${}_4$ transverse Seebeck thermometry

Understanding and controlling heat flow in low-dimensional magnetic materials is central to thermoelectrics and spin caloritronics. One of the challenges is the absence of sensitive probes of small, field-dependent modulations in thermal transport. Here we demonstrate transverse Seebeck thermometry using exfoliated TaIrTe${}_4$ as a probe of thermal conductivity modulated by an external magnetic field on a van der Waals magnet, CrPS${}_4$. With a temperature gradient oriented at ${45}^{\circ }$ to its principal crystallographic axes, TaIrTe${}_4$ exhibits a transverse thermopower exceeding $200\mu \mathrm{V}{\mathrm{K}}^{-1}$ for 900 nm wide and 30 $\mu$m long electrodes, enabling precise detection of variations in the local temperature gradients. Exploiting this with CrPS${}_4$ in a nonlocal geometry, we resolve distinct field dependent thermal conductivity changes associated with both the spin-flip and spin-flop magnetic transitions which we attribute to variations in the magnon$-$phonon coupling in CrPS${}_4$. At 5 K, the transverse Seebeck response is modulated by more than 8$\mathrm{\%}$ by an external magnetic field, demonstrating strong magnetic control of heat transport in CrPS${}_4$. This all van der Waals platform offers high sensitivity to modulations of thermal conductivity and a broad adaptability to a wide range of exfoliated magnetic systems.