@article{MTMT:33644685,
	title = {Electrically driven singlet-triplet transition in triangulene spin-1 chains},
	url = {https://m2.mtmt.hu/api/publication/33644685},
	author = {Martínez-Carracedo, Gabriel and Oroszlány, László and García-Fuente, Amador and Szunyogh, László and Ferrer, Jaime},
	doi = {10.1103/PhysRevB.107.035432},
	journal-iso = {PHYS REV B},
	journal = {PHYSICAL REVIEW B},
	volume = {107},
	unique-id = {33644685},
	issn = {2469-9950},
	year = {2023},
	eissn = {2469-9969},
	orcid-numbers = {Oroszlány, László/0000-0001-5682-6424}
}

@article{MTMT:32575599,
	title = {Relativistic first-principles theory of Yu-Shiba-Rusinov states applied to Mn adatoms and Mn dimers on Nb(110)},
	url = {https://m2.mtmt.hu/api/publication/32575599},
	author = {Nyári, Bendegúz Tamás and Lászlóffy, András and Szunyogh, László and Csire, G and Park, K and Ujfalussy, Balázs},
	doi = {10.1103/PhysRevB.104.235426},
	journal-iso = {PHYS REV B},
	journal = {PHYSICAL REVIEW B},
	volume = {104},
	unique-id = {32575599},
	issn = {2469-9950},
	abstract = {We present a fully relativistic first-principles-based theoretical approach for the calculation of the spectral properties of magnetic impurities on the surface of a superconducting substrate, providing a material specific framework for the investigation of the Yu-Shiba-Rusinov (YSR) states. By using a suitable orbital decomposition of the local densities of states we discuss in great detail the formation of the YSR states for an Mn adatom and for two kinds of Mn dimers placed on the Nb(110) surface and compare our results to recent experimental findings. In the case of the adatom we find that the spin-orbit coupling slightly shifts some of the YSR peaks and also the local spin polarization on the Nb atoms has marginal effects on their positions. Moreover, by scaling the exchange field on the Mn site we could explain the lack of the dx(2)-y(2)-like YSR state in the spectrum. While our results for a close packed ferromagnetic dimer are in satisfactory agreement with the experimentally observed splitting of the YSR states, in the case of an antiferromagnetic dimer we find that the spin-orbit coupling is not sufficiently large to explain the splitting of the YSR states seen in the experiment. Changing the relative orientation of the magnetic moments in this dimer induces splitting of the YSR states and also shifts their energy, leading even to the formation of a zero bias peak in the case of the deepest YSR state.},
	keywords = {SUPERCONDUCTOR},
	year = {2021},
	eissn = {2469-9969},
	orcid-numbers = {Nyári, Bendegúz Tamás/0000-0001-5524-9995}
}

@article{MTMT:32162776,
	title = {Spontaneous creation and annihilation dynamics of magnetic skyrmions at elevated temperature},
	url = {https://m2.mtmt.hu/api/publication/32162776},
	author = {Wang, JL and Strungaru, M and Ruta, S and Meo, A and Zhou, YF and Deák, András and Szunyogh, László and Gavriloaea, PI and Moreno, R and Chubykalo-Fesenko, O and Wu, J and Xu, YB and Evans, RFL and Chantrell, RW},
	doi = {10.1103/PhysRevB.104.054420},
	journal-iso = {PHYS REV B},
	journal = {PHYSICAL REVIEW B},
	volume = {104},
	unique-id = {32162776},
	issn = {2469-9950},
	abstract = {Skyrmions are topologically protected nanoscale magnetic structures with a wide range of potential applications. Here we determine the life cycle of skyrmions from their creation to their intrinsic dynamics and thermal stability to their eventual thermodynamic demise. Using atomistic simulations of Ir/Co/Pt, parameterized from ab initio calculations, we demonstrate the thermal phase transition to a skyrmion state under application of a perpendicular magnetic field. The created skyrmions exhibit Brownian particlelike dynamics driven by the underlying thermal spin fluctuations. At an elevated temperature window well below the Curie temperature, the skyrmions are metastable and can collapse to a uniform magnetic state. With application of an external magnetic field, the intrinsic local thermal spin fluctuations at this elevated temperature window are sufficiently large to allow the spontaneous formation of new skyrmions in thermodynamic equilibrium analogous to a spontaneous skyrmion gas. Such a system could be used to implement a skyrmion-based true random number generator.},
	keywords = {FLUCTUATIONS},
	year = {2021},
	eissn = {2469-9969},
	orcid-numbers = {Deák, András/0000-0002-3210-2947}
}

@article{MTMT:32025792,
	title = {Proper and improper chiral magnetic interactions},
	url = {https://m2.mtmt.hu/api/publication/32025792},
	author = {dos Santos Dias, M. and Brinker, S. and Lászlóffy, András and Nyári, Bendegúz Tamás and Blügel, S. and Szunyogh, László and Lounis, S.},
	doi = {10.1103/PhysRevB.103.L140408},
	journal-iso = {PHYS REV B},
	journal = {PHYSICAL REVIEW B},
	volume = {103},
	unique-id = {32025792},
	issn = {2469-9950},
	year = {2021},
	eissn = {2469-9969},
	orcid-numbers = {Nyári, Bendegúz Tamás/0000-0001-5524-9995}
}

@article{MTMT:32008881,
	title = {Element‐Specific Magnetization Damping in Ferrimagnetic DyCo 5 Alloys Revealed by Ultrafast X‐ray Measurements},
	url = {https://m2.mtmt.hu/api/publication/32008881},
	author = {Abrudan, Radu and Hennecke, Martin and Radu, Florin and Kachel, Torsten and Holldack, Karsten and Mitzner, Rolf and Donges, Andreas and Khmelevskyi, Sergii and Deák, András and Szunyogh, László and Nowak, Ulrich and Eisebitt, Stefan and Radu, Ilie},
	doi = {10.1002/pssr.202100047},
	journal-iso = {PHYS STATUS SOLIDI-R},
	journal = {PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS},
	volume = {15},
	unique-id = {32008881},
	issn = {1862-6254},
	year = {2021},
	eissn = {1862-6270},
	orcid-numbers = {Deák, András/0000-0002-3210-2947; Radu, Ilie/0000-0001-8503-3503}
}

@article{MTMT:31835284,
	title = {L1(0)-ordered (Fe100-xCrx)Pt thin films: Phase formation, morphology, and spin structure},
	url = {https://m2.mtmt.hu/api/publication/31835284},
	author = {Schmidt, Nataliia Y. and Mondal, Ritwik and Donges, Andreas and Hintermayr, Julian and Luo, Chen and Ryll, Hanjo and Radu, Florin and Szunyogh, László and Nowak, Ulrich and Albrecht, Manfred},
	doi = {10.1103/PhysRevB.102.214436},
	journal-iso = {PHYS REV B},
	journal = {PHYSICAL REVIEW B},
	volume = {102},
	unique-id = {31835284},
	issn = {2469-9950},
	abstract = {Chemically ordered L1(0) (Fe100-xCrx)Pt thin films were expitaxially grown on MgO(001) substrates by magnetron sputter-deposition at 770 degrees C. In this sample series, Fe was continuously substituted by Cr over the full composition range. The lattice parameter in the [001] growth direction steadily increases from L1(0) -FePt toward L1(0) -CrPt, confirming the incorporation of Cr in the lattice occupying Fe sites. With the observed high degree of chemical ordering and (001) orientation, strong perpendicular magnetic anisotropy is associated, which persists up to a Cr content of x = 20 at % Similarly, the coercive field in the easy-axis direction is strongly reduced, which is, however, further attributed to a strong alteration of the film morphology with Cr substitution. The latter changes from a well-separated island microstructure to a more continuous film morphology. In the dilute alloy with low Cr content, isolated Cr magnetic moments couple antiferromagnetically to the ferromagnetic Fe matrix. In this case, all Cr moments are aligned parallel, thus forming a ferrimagnetic FeCrPt system. With increasing Cr concentration, nearest-neighbor Cr-Cr pairs start to appear, thereby increasing magnetic frustration and disorder, which lead to canting of neighboring magnetic moments, as revealed by atomistic spin-model simulations with model parameters based on first principles. At higher Cr concentrations, a frustrated ferrimagnetic order is established. With Cr substitution of up to 20 at. %, no pronounced change in Curie temperature, which is in the range of 700 K, was noticed. But with further addition the Curie temperature drops down substantially even down to room temperature at 47 at. % Cr. Furthermore, x-ray magnetic circular dichroism studies on dilute alloys containing up to 20 at. % of Cr revealed similar spin moments for Fe and Cr in the range between 2.1-2.5 mu B but rather large orbital moments of up to 0.50 +/- 0.10 mu B for Cr. These results were also compared to ab initio calculations.},
	year = {2020},
	eissn = {2469-9969},
	orcid-numbers = {Nowak, Ulrich/0000-0003-2925-6774}
}

@article{MTMT:31645800,
	title = {Noncollinear antiferromagnetic states in Ru-based Hensler compounds induced by biquadratic coupling},
	url = {https://m2.mtmt.hu/api/publication/31645800},
	author = {Simon, Eszter and Donges, Andreas and Szunyogh, László and Nowak, Ulrich},
	doi = {10.1103/PhysRevMaterials.4.084408},
	journal-iso = {PHYS REV MAT},
	journal = {PHYSICAL REVIEW MATERIALS},
	volume = {4},
	unique-id = {31645800},
	issn = {2475-9953},
	abstract = {We investigate the magnetic properties of Ru(2)MnZ (Z = Sn, Sb, Ge, Si) chemically ordered, full Heusler compounds for zero as well as finite temperatures. Based on first-principles calculations we derive the interatomic isotropic bilinear and biquadratic couplings between Mn atoms from the paramagnetic state. We find frustrated isotropic couplings for all compounds and, in the case of Z = Si and Sb, a nearest-neighbor biquadratic coupling that favors perpendicular alignment between the Mn spins. By using an extended classical Heisenberg model in combination with spin dynamics simulations we obtain the magnetic equilibrium states. From these simulations we conclude that the biquadratic coupling, in combination with the frustrated isotropic interactions, leads to noncollinear magnetic ground states in the Ru2MnSi and Ru2MnSb compounds. In particular, for these alloys we find two distinct, noncollinear ground states which are energetically equivalent and can be identified as 3Q and 4Q states on a frustrated fcc lattice. Investigating the thermal stability of the noncollinear phase we find that, in the case of Ru2MnSi, the multiple-Q phase undergoes a transition to the single Q phase, while in case of Ru2MnSb the corresponding transition is not obtained due to the larger magnitude of the nearest-neighbor biquadratic coupling.},
	keywords = {GE; PHASE-TRANSITIONS; MAGNETIC-STRUCTURES; COO; Heusler},
	year = {2020},
	eissn = {2475-9953},
	orcid-numbers = {Simon, Eszter/0000-0003-3527-1233; Nowak, Ulrich/0000-0003-2925-6774}
}

@article{MTMT:31645795,
	title = {Spin reorientation transition in an ultrathin Fe film on W(110) induced by Dzyaloshinsky-Moriya interactions},
	url = {https://m2.mtmt.hu/api/publication/31645795},
	author = {Nagyfalusi, Balázs and Udvardi, László and Szunyogh, László and Rózsa, Levente},
	doi = {10.1103/PhysRevB.102.134413},
	journal-iso = {PHYS REV B},
	journal = {PHYSICAL REVIEW B},
	volume = {102},
	unique-id = {31645795},
	issn = {2469-9950},
	abstract = {Controlling the preferred direction of the magnetic moments is essential for the design of spintronic devices based on ultrathin films and heterostructures. As the film thickness or the temperature is increased, the easy anisotropy axis is typically reoriented from an out-of-plane direction preferred by surface and interface energy contributions to an in-plane alignment favored by the volume anisotropy terms. We study the temperature-driven spin reorientation transition in two atomic layers of Fe on W(110) using well-tempered metadynamics simulations based on a spin model parametrized by ab initio calculations and find that the transition only takes place in the presence of the Dzyaloshinsky-Moriya interaction (DMI). This demonstrates that the chiral DMI does not only differentiate between noncollinear spin structures of different rotational senses, but it also influences the magnetic orientation of collinear magnetic configurations.},
	keywords = {MAGNETIC-ANISOTROPY; Materials Science, Multidisciplinary; Physics, Applied; FE(110)},
	year = {2020},
	eissn = {2469-9969},
	orcid-numbers = {Rózsa, Levente/0000-0001-9456-5755}
}

@article{MTMT:30869235,
	title = {Weak ferromagnetism in hexagonal Mn(3)Z alloys (Z = Sn, Ge, Ga)},
	url = {https://m2.mtmt.hu/api/publication/30869235},
	author = {Nyári, Bendegúz Tamás and Deák, András and Szunyogh, László},
	doi = {10.1103/PhysRevB.100.144412},
	journal-iso = {PHYS REV B},
	journal = {PHYSICAL REVIEW B},
	volume = {100},
	unique-id = {30869235},
	issn = {2469-9950},
	abstract = {We present combined spin model and first-principles electronic-structure calculations to study the weak ferromagnetism in bulk Mn(3)Z (Z = Sn, Ge, Ga) compounds. The spin-model parameters were determined from a spin-cluster expansion technique based on the relativistic disordered local moment formalism implemented in the screened Korringa-Kohn-Rostoker method. We describe the magnetic ground state of the system within a three-sublattice model and investigate the formation of the weak ferromagnetic states in terms of the relevant model parameters. First, we give a group-theoretical argument how the point-group symmetry of the lattice leads to the formation of weak ferromagnetic states. Then we study the ground states of the classical spin model and derive analytical expressions for the weak ferromagnetic distortions by recovering the main results of the group-theoretical analysis. As a third approach, we obtain the weak ferromagnetic ground states from self-consistent density-functional calculations and compare our results with previous first-principles calculations and with available experimental data. In particular, we demonstrate that the orbital moments follow a decomposition predicted by group theory. For a deeper understanding of the formation of weak ferromagnetism, we selectively trace the effect of the spin-orbit coupling at the Mn and Z sites. In addition, for the case of Mn3Ga, we gain information on the role of the induced moment of Ga from constrained local density-functional calculations.},
	keywords = {Materials Science, Multidisciplinary; Physics, Applied; MAGNETIC-STRUCTURE},
	year = {2019},
	eissn = {2469-9969},
	orcid-numbers = {Nyári, Bendegúz Tamás/0000-0001-5524-9995; Deák, András/0000-0002-3210-2947}
}

@article{MTMT:30869234,
	title = {Spin-spiral formalism based on the multiple-scattering Green's function technique with applications to ultrathin magnetic films and multilayers},
	url = {https://m2.mtmt.hu/api/publication/30869234},
	author = {Simon, Eszter and Szunyogh, László},
	doi = {10.1103/PhysRevB.100.134428},
	journal-iso = {PHYS REV B},
	journal = {PHYSICAL REVIEW B},
	volume = {100},
	unique-id = {30869234},
	issn = {2469-9950},
	abstract = {Based on the Korringa-Kohn-Rostoker Green's function technique, we present a computational scheme for calculating the electronic structure of layered systems with homogeneous spin-spiral magnetic state. From the self-consistent nonrelativistic calculations, the total energy of the spin-spiral states is determined as a function of the wave vector, while a relativistic extension of the formalism in first order of the spin-orbit coupling gives an access to the effect of the Dzyaloshinskii-Moriya interactions. We demonstrate that the newly developed method properly describes the magnetic ground state of a Mn monolayer on W(001) and that of a Co monolayer on Pt(111). The obtained spin-spiral energies are mapped to a classical spin model, the parameters of which are compared to those calculated directly from the relativistic torque method. In case of the Co/Pt(111) system, we find that the isotropic interaction between the Co atoms is reduced and the Dzyaloshinskii-Moriya interaction is increased when capped by a Ru layer. In addition, we perform spin-spiral calculations on Ir/Fe/Co/Pt and Ir/Co/Fe/Pt multilayer systems and find a spin-spiral ground state with very long wavelength due to the frustrated isotropic couplings between the Fe atoms, whereas the Dzyaloshinskii-Moriya interaction strongly depends on the sequence of the Fe and Co layers.},
	keywords = {STATES; METALS; CRYSTALS; Anisotropy; BAND-STRUCTURE; SKYRMIONS; Exchange interactions; Materials Science, Multidisciplinary; Physics, Applied; ENERGY-ELECTRON DIFFRACTION; CELLULAR METHOD},
	year = {2019},
	eissn = {2469-9969}
}