Abstrakt
Antiferromagnetic materials opened up a new avenue of research with potential use in spintronic devices [1]. Compared to their ferromagnetic counterparts antiferromagnets exhibit faster dynamics, insensitivity to the external magnetic fields, and absence of stray fields promising higher integration density.
Some functionalities of the antiferromagnetic spintronic devices such as readout using anisotropic magnetoresistance or reorientation of magnetic axis using current-induced spin-orbit torque [2] are directly derived from their ferromagnetic counterparts whereas other functionalities are unique to the antiferromagnets. One of these is the Quenching of the antiferromagnet into high resistivity states using electrical and optical pulses which was recently discovered in epitaxially grown thin CuMnAs films [3]. This effect is based on the change of the magnetic structure of the antiferromagnet induced by the application of high energy pulse driving the system to the vicinity of Néel temperature and its subsequent fast cooling resulting in quenching of the highly resistive disordered magnetic state. The observed changes of resistivity reach tens of percent at room temperature and even 100 percent at low temperatures and exceed by two orders of magnitude the change of the resistivity based on anisotropic magnetoresistance induced by the reorientation of the spin axis [2].
In this contribution, we provide an overview of detailed experimental characterization of quenching of CuMnAs using a single ultrashort laser pulse for excitation. We focus on the optimization of the electrical readout response of the Hall-bar devices with regard to pulse length, and fluency. It provides an overview of the response for CuMnAs films with varying thickness and substrate material. Lastly, this contribution evaluates the effects of permanent damage caused by laser pulse excitation with proposed damage mitigation techniques.
[1] Jungwirth, T., Marti, X., Wadley, P. et al. Antiferromagnetic spintronics. Nature Nanotech 11, 231-241 (2016). https://doi.org/10.1038/nnano.2016.18
[2] Wadley, P. et al. Electrical switching of an antiferromagnet. Science 351, 587-590 (2016). https://doi.org/10.1126/science.aab1031
[3] Kašpar, Z., Surýnek, M., Zubáč, J. et al. Quenching of an antiferromagnet into high resistivity states using electrical or ultrashort optical pulses. Nat Electron 4, 30-37 (2021). https://doi.org/10.1038/s41928-020-00506-4