Research

A joint publication with Helen Gomonay about antiferromagnetic hysteresis above the spin flop field has been published in Physical Review B.

They demonstrate that external magnetic fields change the magnetic anisotropy in the antiferromagnet CoO. THis is shown by measuring hysteresis curves for magnetic fields higher than the spin flop field. This behavior is shown to agree with the presence of the unquenched orbital momentum, which can play an important role in antiferromagnetic spintronics.

You can find the publication under PhysRevB.107.L060403.

A joint publication with Jairo Sinova and Libor Šmejkal about the spontaneous anomalous Hall effect in a magnetic semicoductor has been published in Physical Review Letters.

They observe a spontaneoeus anomalous Hall signal without external magnetic fields in the semiconductor MnTe. The anomalous Hall effect arises from an unconventional phase with strong time-reversal symmetry breaking and alternating spin polarization in real-space crystal structure and momentum-space electronic structure.

You can find the publication under PhysRevLett.130.036702

A joint publication with Helen Gomonay about  domains the canted antiferromagnet hematite has been published in Physical Review B.

They study the domain structure of hematite and the influence of destressing fields on the magnetic domain structure. They find fluctuating destressing fields throughout the sample which leads to locally varying effective anisotropies. This effect strongly distinguishes such canted antiferromagnets from collinear ones and gives a foundation for further studies.

You can find the publication under PhysRevB.106.224419.

A publication of Jairo Sinova, Libor Šmejkal and Thomas Jungwirth about altermagnetism, a new nonrelativistic magnetic phase has been published in Physical Review X.

A few month ago a new magnetic phase (altermagnetism) has been proposed. Altermagnets have zero net magnetization (like antiferromagnets) yet spin split electronic bands (like ferromagnets). This paper describes the theoretic framework and orders recent research in the emerging field.

You can find the publication under PhysRevX.12.040501

 

A joint publication with Jairo Sinova and Libor Šmejkal about the anomalous Hall effect in RuO2 has been published in Nature electronics.

They observe an anomalous Hall effect in the altermagnet RuO2 which has no net magnetization yet spin split electronic bands. They further show that, that the anomalous Hall effect dominates over an ordinary Hall contribution. This could lead to the exploration of topological Berry phases and dissipationless quantum transport in crystals of abundant elements and with a compensated antiparallel magnetic order.

You can find the publication under nature.com/articles/s41928-022-00866-z.

A joint publication with Jairo Sinova and Libor Šmejkal about spin transport in the canted antiferromagnet YFeO3 has been published in Nature Communications.

They report long range spin transport in YFeO3 by a transport mechanism that is combined from the Dzyaloshinskii-Moriya interaction and externally applied fields. The decay length of spin waves is determined to be hundreds of nanometers and is strongly anisotropic. This result opens the possibility to use the large class of canted antiferromagnets in the technologically relevant field of long range spin transport.

You can find the publication under nature.com/articles/s41467-022-33520-5.

A joint publication with Helen Gomonay about shape dependent magnetoelastic effects in the antiferromagnet NiO has been published in Physical Review B.

They demonstrate that the antiferromagnetic order in NiO/Pt films can be manipulated via strains. Experiments guided by theoretical models suggest that shape dependent strains require special attention in the design of antiferromagnetic devices.

You can find the publication under PhysRevB.106.094430.

A publication of Jairo Sinova, Libor Šmejkal and Thomas Jungwirth about altermagnetism, a  new nonrelativistic magnetic phase has been published in Physical Review X.

By the use of spin symmetries they predict a new nonrelativistic magnetic phase, namely altermagnetism. Altermagnets have zero net magnetization (like antiferromagnets) yet spin split electronic bands (like ferromagnets). Such materials are promising candidates for future spintronic devices which combile the advanteges from ferromagnets and antiferromagnets.

You can find the publication under PhysRevX.12.031042

A joint publication with Helen Gomonay about noncollinear spin currents for switching of chiral magnetic textures has been published in PRL.

They demonstrate the combined generation of broadband and narrowband magnons in thin films of NiO/Pt. They present two excitation processes which both lead to the emmision of THz signals. These results open new routes towards the development of fast opto-spintronic devices based on antiferromagnetic materials.

They propose a concept of noncollinear spin current, whose spin polarization varies in space even in nonmagnetic crystals.  Moreover, by referring to atomistic spin dynamics simulations they show that noncollinear spin currents can be used to switch the chiral spin texture of Mn3X in a deterministic way even in the absence of an external magnetic field. Their theoretical prediction can be readily tested in experiments, which will open a novel route toward electric control of complex spin structures in noncollinear antiferromagnets.

You can find the publication under Phys. Rev. Lett. 129, 097204.

A joint publication with Libor Šmejkal about the parity violations of the electronic structure in the antiferromagnet Mn2Au has been published in Journal of Physics: Condensed Matter.

They perform momentum resolved photemission on individual antiferromagnetic domains. The results show an asymmetry of the energy with respect to momentum. The responsible spin–orbit interaction couples the broken parity to the Néel order parameter direction. With this foundation they demonstrate a novel tool to image the Néel vector direction, N, by combining spatially resolved momentum microscopy with ab-initio calculations that correlate the broken parity with the vector.

You can find the publication under iopscience.iop.org/article/10.1088/1361-648X/ac87e6.