0000000001319407
AUTHOR
Francesco Maccherozzi
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…
Mechanism of Néel Order Switching in Antiferromagnetic Thin Films Revealed by Magnetotransport and Direct Imaging.
We probe the current-induced magnetic switching of insulating antiferromagnet/heavy metals systems, by electrical spin Hall magnetoresistance measurements and direct imaging, identifying a reversal occurring by domain wall (DW) motion. We observe switching of more than one third of the antiferromagnetic domains by the application of current pulses. Our data reveal two different magnetic switching mechanisms leading together to an efficient switching, namely the spin-current induced effective magnetic anisotropy variation and the action of the spin torque on the DWs.
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…
Imaging of current induced Néel vector switching in antiferromagnetic Mn 2 Au
The effects of current induced N\'eel spin-orbit torques on the antiferromagnetic domain structure of epitaxial Mn$_2$Au thin films were investigated by X-ray magnetic linear dichroism - photoemission electron microscopy (XMLD-PEEM). We observed current induced switching of AFM domains essentially corresponding to morphological features of the samples. Reversible as well as irreversible N\'eel vector reorientation was obtained in different parts of the samples and the switching of up to 30 % of all domains in the field of view of 10 $\mu$m is demonstrated. Our direct microscopical observations are compared to and fully consistent with anisotropic magnetoresistance effects previously attribu…
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…
Role of B diffusion in the interfacial Dzyaloshinskii-Moriya interaction inTa/Co20Fe60B20/MgOnanowires
We report on current-induced domain wall motion in $\mathrm{Ta}/\mathrm{C}{\mathrm{o}}_{20}\mathrm{F}{\mathrm{e}}_{60}{\mathrm{B}}_{20}/\mathrm{MgO}$ nanowires. Domain walls are observed to move against the electron flow when no magnetic field is applied, while a field along the nanowires strongly affects the domain wall motion velocity. A symmetric effect is observed for up-down and down-up domain walls. This indicates the presence of right-handed domain walls, due to a Dzyaloshinskii-Moriya interaction (DMI) with a DMI coefficient $D=+0.06\phantom{\rule{0.16em}{0ex}}\mathrm{mJ}/{\mathrm{m}}^{2}$. The positive DMI coefficient is interpreted to be a consequence of B diffusion into the Ta bu…
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)