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The recently reported magnetic ordering in insulating two-dimensional (2D) materials, such as chromium triiodide (CrI$_3$) and chromium tribromide (CrBr$_3$), opens new possibilities for the fabrication of magneto-electronic devices based on 2D systems. Inevitably, the magnetization and spin dynamics in 2D magnets are strongly linked to Joule heating. Therefore, understanding the coupling between spin, charge and heat, i.e. spin caloritronic effects, is crucial. However, spin caloritronics in 2D ferromagnets remains mostly unexplored, due to their instability in air. Here we develop a fabrication method that integrates spin-active contacts with 2D magnets through hBN encapsulation, allowing us to explore the spin caloritronic effects in these materials. The angular dependence of the thermal spin signal of the CrBr$_3$/Pt system is studied, for different conditions of magnetic field and heating current. We highlight the presence of a significant magnetic proximity effect from CrBr$_3$ on Pt revealed by an anomalous Nernst effect in Pt, and suggest the contribution of the spin Seebeck effect from CrBr$_3$. These results pave the way for future magnonic devices using air-sensitive 2D magnetic insulators.

The demand for compact, high-speed and energy-saving circuitry urges higher efficiency of spintronic devices that can offer a viable alternative for the current electronics. The route towards this goal suggests implementing two-dimensional (2D) materials that provide large spin polarization of charge current together with the long-distance transfer of the spin information. Here, for the first time, we experimentally demonstrate a large spin polarization of the graphene conductivity ($\approx 14\%$) arising from a strong induced exchange interaction in proximity to a 2D layered antiferromagnetic. The strong coupling of charge and spin currents in graphene with high efficiency of spin current generation, comparable to that of metallic ferromagnets, together with the observation of spin-dependent Seebeck and anomalous Hall effects, all consistently confirm the magnetic nature of graphene. The high sensitivity of spin transport in graphene to the magnetization of the outermost layer of the adjacent interlayer antiferromagnet, also provides a tool to read out a single magnetic sub-lattice. The first time observations of the electrical and thermal generation of spin currents by magnetic graphene suggest it as the ultimate building block for ultra-thin magnetic memory and sensory devices, combining gate tunable spin-dependent conductivity, long-distance spin transport and spin-orbit coupling all in a single 2D material.