0000000000428537
AUTHOR
Felix Schreiber
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…
Direct imaging of current-induced antiferromagnetic switching revealing a pure thermomagnetoelastic switching mechanism in NiO
We unambiguously identify the origin of the current-induced magnetic switching of insulating antiferromagnet/heavy metal bilayers. Previously, different reorientations of the Neel order for the same current direction were reported for different device geometries and different switching mechanisms were proposed. Here, we combine concurrent electrical readout and optical imaging of the switching of antiferromagnetic domains with simulations of the current-induced temperature and strain gradients. By comparing the switching in specially engineered NiO/Pt device and pulsing geometries, we can rule out spin-orbit torque based mechanisms and identify a thermomagnetoelastic mechanism to dominate t…
An insulating doped antiferromagnet with low magnetic symmetry as a room temperature spin conduit
We report room temperature long-distance spin transport of magnons in antiferromagnetic thin film hematite doped with Zn. The additional dopants significantly alter the magnetic anisotropies, resulting in a complex equilibrium spin structure that is capable of efficiently transporting spin angular momentum at room temperature without the need for a well-defined, pure easy-axis or easy-plane anisotropy. We find intrinsic magnon spin-diffusion lengths of up to 1.5 {\mu}m, and magnetic domain governed decay lengths of 175 nm for the low frequency magnons, through electrical transport measurements demonstrating that the introduction of non-magnetic dopants does not strongly reduce the transport…
Electrical detection of the spin reorientation transition in antiferromagnetic TmFeO3 thin films by spin Hall magnetoresistance
TmFeO$_3$ (TFO) is a canted antiferromagnet that undergoes a spin reorientation transition (SRT) with temperature between 82 K and 94 K in single crystals. In this temperature region, the N\'eel vector continuously rotates from the crystallographic $c$-axis (below 82 K) to the $a$-axis (above 94 K). The SRT allows for a temperature control of distinct antiferromagnetic states without the need for a magnetic field, making it apt for applications working at THz frequencies. For device applications, thin films of TFO are required as well as an electrical technique for reading out the magnetic state. Here we demonstrate that orthorhombic TFO thin films can be grown by pulsed laser deposition an…
Identification of Néel Vector Orientation in Antiferromagnetic Domains Switched by Currents in NiO/Pt Thin Films
Understanding the electrical manipulation of the antiferromagnetic order is a crucial aspect to enable the design of antiferromagnetic devices working at THz frequencies. Focusing on collinear insulating antiferromagnetic $\mathrm{Ni}\mathrm{O}/\mathrm{Pt}$ 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 [$\ifmmode\pm\else\textpm\fi{}5$ $\ifmmode\pm\else\textpm\fi{}5$ 19], different compared to the bulk $⟨112⟩$ d…
Concurrent magneto-optical imaging and magneto-transport readout of electrical switching of insulating antiferromagnetic thin films
We demonstrate stable and reversible current induced switching of large-area ($> 100\;��m^2$) antiferromagnetic domains in NiO/Pt by performing concurrent transport and magneto-optical imaging measurements in an adapted Kerr microscope. By correlating the magnetic images of the antiferromagnetic domain changes and magneto-transport signal response in these current-induced switching experiments, we disentangle magnetic and non-magnetic contributions to the transport signal. Our table-top approach establishes a robust procedure to subtract the non-magnetic contributions in the transport signal and extract the spin-Hall magnetoresistance response associated with the switching of the antifer…
Direct Imaging of Current-Induced Antiferromagnetic Switching Revealing a Pure Thermomagnetoelastic Switching Mechanism in NiO.
We unravel the origin of current-induced magnetic switching of insulating antiferromagnet/heavy metal systems. We utilize concurrent transport and magneto-optical measurements to image the switching of antiferromagnetic domains in specially engineered devices of NiO/Pt bilayers. Different electrical pulsing and device geometries reveal different final states of the switching with respect to the current direction. We can explain these through simulations of the temperature induced strain and we identify the thermomagnetoelastic switching mechanism combined with thermal excitations as the origin, in which the final state is defined by the strain distributions and heat is required to switch th…
Electrical detection of the spin reorientation transition in antiferromagnetic TmFeO3 thin films by spin Hall magnetoresistance
$\mathrm{Tm}\mathrm{Fe}{\mathrm{O}}_{3}$ (TFO) is a canted antiferromagnet that undergoes a spin reorientation transition (SRT) with temperature between 82 and 94 K in single crystals. In this temperature region, the N\'eel vector continuously rotates from the crystallographic $c$ axis (below 82 K) to the $a$ axis (above 94 K). The SRT allows for a temperature control of distinct antiferromagnetic states without the need for a magnetic field, making it apt for applications working at terahertz frequencies. For device applications, thin films of TFO are required as well as an electrical technique for read-out of the magnetic state. Here, we demonstrate that orthorhombic TFO thin films can be…
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 "An insulating doped antiferromagnet with low magnetic symmetry as a room temperature spin conduit "
Data for the article "An insulating doped antiferromagnet with low magnetic symmetry as a room temperature spin conduit " (https://aip.scitation.org/doi/full/10.1063/5.0032940 and https://arxiv.org/abs/2011.09755)
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).