0000000000102144
AUTHOR
Christin Schmitt
Single device offset-free magnetic field sensing principle with tunable sensitivity and linear range based on spin-orbit-torques
We propose a novel device concept using spin-orbit-torques to realize a magnetic field sensor, where we eliminate the sensor offset using a differential measurement concept. We derive a simple analytical formulation for the sensor signal and demonstrate its validity with numerical investigations using macrospin simulations. The sensitivity and the measurable linear sensing range in the proposed concept can be tuned by either varying the effective magnetic anisotropy or by varying the magnitude of the injected currents. We show that undesired perturbation fields normal to the sensitive direction preserve the zero-offset property and only slightly modulate the sensitivity of the proposed sens…
Mechanism of electrical switching of ultra-thin CoO/Pt bilayers
We study current-induced switching of the N\'eel vector in CoO/Pt bilayers to understand the underlaying antiferromagnetic switching mechanism. Surprisingly, we find that for ultra-thin CoO/Pt bilayers electrical pulses along the same path can lead to an increase or decrease of the spin Hall magnetoresistance signal, depending on the current density of the pulse. By comparing the results of these electrical measurements to XMLD-PEEM imaging of the antiferromagnetic domain structure before and after the application of current pulses, we reveal the reorientation of the N\'eel vector in ultra-thin CoO(4 nm). This allows us to determine that even opposite resistance changes can result from a th…
Identification of Néel vector orientation in antiferromagnetic domains switched by currents in NiO/Pt thin films
Understanding the electrical manipulation of antiferromagnetic order is a crucial aspect to enable the design of antiferromagnetic devices working at THz frequency. Focusing on collinear insulating antiferromagnetic NiO/Pt thin films as a materials platform, we identify the crystallographic orientation of the domains that can be switched by currents and quantify the N\'eel vector direction changes. We demonstrate electrical switching between different T-domains by current pulses, finding that the N\'eel vector orientation in these domains is along $[\pm5\ \pm5\ 19]$, different compared to the bulk $$ directions. The final state of the N\'eel vector $\textbf{n}$ switching after current pulse…
Strain-induced Shape Anisotropy in Antiferromagnetic Structures
We demonstrate how shape dependent strain can be used to control antiferromagnetic order in NiO Pt thin films. For rectangular elements patterned along the easy and hard magnetocrystalline anisotropy axes of our film, we observe different domain structures and we identify magnetoelastic interactions that are distinct for different domain configurations. We reproduce the experimental observations by modeling the magnetoelastic interactions, considering spontaneous strain induced by the domain configuration, as well as elastic strain due to the substrate and the shape of the patterns. This allows us to demonstrate and explain how the variation of the aspect ratio of rectangular elements can b…
Data of the article "Efficient spin torques in antiferromagnetic CoO/Pt quantified by comparing field- and current- induced switching"
Data for experimental transport measurements and analytical calculations for the article "Efficient spin torques in antiferromagnetic CoO/Pt quantified by comparing field- and current- induced switching" (https://arxiv.org/abs/2003.05923)
Data for the article "Magnetic Sensitivity Distribution of Hall Devices in Antiferromagnetic Switching Experiments"
Data for the article "Magnetic Sensitivity Distribution of Hall Devices in Antiferromagnetic Switching Experiments" URL: https://link.aps.org/doi/10.1103/PhysRevApplied.16.064023 DOI: 10.1103/PhysRevApplied.16.064023
Data for the article "Strain-induced shape anisotropy in antiferromagnetic structures"
Data for the article "Strain-induced shape anisotropy in antiferromagnetic structures" URL: https://link.aps.org/doi/10.1103/PhysRevB.106.094430 DOI: 10.1103/PhysRevB.106.094430
Data for the article "Concurrent magneto-optical imaging and magneto-transport readout of electrical switching of insulating antiferromagnetic thin films"
Data for experimental transport measurements and optical imaging for the article "Concurrent magneto-optical imaging and magneto-transport readout of electrical switching of insulating antiferromagnetic thin films" (https://arxiv.org/abs/2004.13374).