We examine the thermal origin of the detected "saw-tooth"shaped Hall resistance (R xy) signals in the spin-orbit torque switching experiment for antiferromagnetic MnN. Compared with the results of the heavy metal/antiferromagnet bilayers (MnN/Ta), the qualitatively same "saw-tooth"shaped signals also appear in the samples with the heavy metal layer alone (either Ta or Pt) without the MnN layer. In addition, the R xy signal changes oppositely in the devices with Ta and Pt, due to the opposite temperature coefficient of resistivity of the two materials. All those results are consistent with the "localized Joule heating"mechanism in devices with Hall crosses geometry. Moreover, by utilizing a structure with separated writing current paths and Hall cross area, the quadratic relationship between Δ R xy and the writing current's amplitude is observed, which provides quantitative evidence of the thermal contribution. These results reveal the dominant thermal artifact in the widely used Hall crosses geometry for Néel vector probing and also provide a strategy to semi-quantitatively evaluate the thermal effect, which can shed light on a more conclusive experiment design.
Bibliographical noteFunding Information:
This work was initially supported by The Center for Spintronic Materials, Interfaces, and Novel Architectures (C-SPIN), one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by Microelectronics Advanced Research Corporation (MARCO) and Defense Advanced Research Projects Agency (DARPA). This work was later supported in part by Applications and Systems driven Center for Energy-Efficient Integrated NanoTechnologies (ASCENT), one of the six centers in Joint University Microelectronics Program (JUMP), a Semiconductor Research Corporation (SRC) program sponsored by DARPA. Portions of this work were conducted in the Minnesota Nano Center, which is supported by the National Science Foundation (NSF) through the National Nano Coordinated Infrastructure Network (NNCI) under Award No. ECCS-2025124.
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