Graphene and hexagonal boron nitride (hBN) have shown fascinating features in spintronics due to their metallic and tunneling behaviors, respectively. In this work, we report for the first time room temperature spin valve effect in NiFe/Gr–hBN/Co configuration.

The two-dimensional (2D) layered electronic materials of transition metal dichalcogenides (TMDCs) have been recently proposed as an emerging canddiate for spintronic applications. Here, we report the exfoliated single layer WS2-intelayer based spin valve effect in NiFe/WS2/Co junction from room temperature to 4.2 K. The ratio of relative magnetoresistance in spin valve effect increases from 0.18% at room temperature to 0.47% at 4.2 K. We observed that the junction resistance decreases monotonically as temperature is lowered. These results revealed that semiconducting WS2 thin film works as a metallic conducting interlayer between NiFe and Co electrodes.

We demonstrate the modification of the electronic properties of single layer chemical vapor deposition (CVD)-grown graphene by deep ultraviolet (DUV) light irradiation. The shift in the G and 2D bands in Raman spectra towards higher wavenumber suggests p-doping in graphene field effect transistors (FETs). In the transport measurements, the Dirac point is shifted towards positive gate voltage with increasing DUV light exposure time, revealing the strong p-doping effect without a large resistance increase. The doping is found to be stable in graphene devices, with a slight change in mobilities. We also constructed a p-n junction by DUV light exposure on selected regions of graphene, and investigated it with gate voltage dependent resistivity measurements and currentvoltage characteristics.

The magnetotransport properties of spin valve structure are highly influenced by the type of intervening layer inserted between the ferromagnetic electrodes. In this scenario, spin filtering effect at the interfaces plays a crucial role in determining the magnetoresistance (MR) of such magnetic structures, which can be enhanced by using a suitable intervening layer. Here, the authors investigate the spin filtering effect of the two-dimensional layers such as hexagonal boron nitride (hBN), graphene (Gr), and Gr-hBN hybrid system for modifying the magnetotransport characteristics of the vertical spin valve architectures (Ni/hBN/Ni, Ni/Gr/Ni, and Ni/Gr-hBN/Ni). Compared to graphene, hBN incorporated magnetic junction reveals higher MR and spin polarizations (P) suggesting better spin filtering at the interfaces. The MR for hBN incorporated junction is calculated to be %0.83%, while that of graphene junction it is estimated to be %0.16%. Similar contrast is observed in the 'P' of ferromagnets (FMs) for the two junctions, that is, %6.4% for hBN based magnetic junction and %2.8% for graphene device. However, for Gr-hBN device, the signal not only get inverts, but it also suggests efficient spin filtering mechanism at the FM interfaces. Their results can be useful to comprehend the origin of spin filtering and the choice of non-magnetic spacer for magnetotransport characteristics.

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