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arXiv · 2501.16736

Laser patterning of the room temperature van der Waals ferromagnet 1$T$-CrTe$_2$

Tristan Riccardi·Suman Sarkar·Anike Purbawati·Aloïs Arrighi·Marek Kostka·Abdellali Hadj-Azzem·Jan Vogel·Julien Renard·Laëtitia Marty·Amit Pawbake·Clément Faugeras·Kenji Watanabe·Takashi Taniguchi·Aurore Finco·Vincent Jacques·Lei Ren·Xavier Marie·Cedric Robert·Manuel Nuñez-Regueiro·Nicolas Rougemaille·Nedjma Bendiab·Johann Coraux
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Abstract

Lamellar crystalline materials, whose layers are bond by van der Waals forces, can be stacked to form ultrathin artificial heterostructures, and in particular vertical magnetic junctions when some of the stacked materials are (ferro)magnetic. Here, using the room temperature van der Waals ferromagnet 1$T$-CrTe$_2$, we report a method for patterning lateral magnetic junctions. Exploiting the heat-induced phase transformation of the material into Cr$_x$Te$_y$ compounds ($x/y>1/2$), we use local laser heating to imprint patterns at the micron-scale. Optimizing laser heat dissipation, we further demonstrate the crucial role of the substrate to control the phase transformation. If plain, unstructured poorly heat-conducting substrates allow for direct writing of magnetic patterns, structured $h$-BN layers can serve as heat stencils to draw potentially thinner patterns. Besides, $h$-BN encapsulation turns out to be heat-protective (in addition from protecting against oxidation as it is generally used for), allowing the demonstration of room temperature ferromagnetism in $<$7~nm-thick 1$T$-CrTe$_2$.

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Tristan Riccardi, Suman Sarkar, Anike Purbawati, Aloïs Arrighi, Marek Kostka, Abdellali Hadj-Azzem, Jan Vogel, Julien Renard, Laëtitia Marty, Amit Pawbake, Clément Faugeras, Kenji Watanabe, Takashi Taniguchi, Aurore Finco, Vincent Jacques, Lei Ren, Xavier Marie, Cedric Robert, Manuel Nuñez-Regueiro, Nicolas Rougemaille, Nedjma Bendiab, Johann Coraux. 2025-01-28. Laser patterning of the room temperature van der Waals ferromagnet 1$T$-CrTe$_2$. https://doi.org/10.1103/physrevmaterials.9.024001

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