@article{MTMT:34749006, title = {Chemical potential of magnetic skyrmion quasiparticles in heavy-metal/iron bilayers}, url = {https://m2.mtmt.hu/api/publication/34749006}, author = {Nagyfalusi, Balázs and Udvardi, László and Szunyogh, László and Rózsa, Levente}, doi = {10.1103/PhysRevB.109.094418}, journal-iso = {PHYS REV B}, journal = {PHYSICAL REVIEW B}, volume = {109}, unique-id = {34749006}, issn = {2469-9950}, year = {2024}, eissn = {2469-9969}, orcid-numbers = {Rózsa, Levente/0000-0001-9456-5755} } @article{MTMT:34470105, title = {Relativistic magnetic interactions from nonorthogonal basis sets}, url = {https://m2.mtmt.hu/api/publication/34470105}, author = {Martínez-Carracedo, G. and Oroszlány, László and García-Fuente, A. and Nyári, Bendegúz Tamás and Udvardi, László and Szunyogh, László and Ferrer, J.}, doi = {10.1103/PhysRevB.108.214418}, journal-iso = {PHYS REV B}, journal = {PHYSICAL REVIEW B}, volume = {108}, unique-id = {34470105}, issn = {2469-9950}, year = {2023}, eissn = {2469-9969}, orcid-numbers = {Oroszlány, László/0000-0001-5682-6424; Nyári, Bendegúz Tamás/0000-0001-5524-9995} } @article{MTMT:32896293, title = {Topological charges of fullerenes}, url = {https://m2.mtmt.hu/api/publication/32896293}, author = {Udvardi, László and László, István}, doi = {10.1007/s10910-022-01354-7}, journal-iso = {J MATH CHEM}, journal = {JOURNAL OF MATHEMATICAL CHEMISTRY}, volume = {61}, unique-id = {32896293}, issn = {0259-9791}, abstract = {We defined the topological charge and bump number for fullerenes. All even fullerene isomers from C-20 up to C-70 were constructed. After optimizing the geometry of the molecules the relation between the topological charge, the bump number and the atomization energy were analysed.}, keywords = {FULLERENES; Chemistry, Multidisciplinary; Skyrmion}, year = {2023}, eissn = {1572-8897}, pages = {335-342} } @article{MTMT:33041619, title = {Magnetic ground state of supported monatomic Fe chains from first principles}, url = {https://m2.mtmt.hu/api/publication/33041619}, author = {Nagyfalusi, Balázs and Udvardi, László and Szunyogh, László}, doi = {10.1088/1361-648X/ac8260}, journal-iso = {J PHYS CONDENS MAT}, journal = {JOURNAL OF PHYSICS-CONDENSED MATTER}, volume = {34}, unique-id = {33041619}, issn = {0953-8984}, abstract = {A new computational scheme is presented based on a combination of the conjugate gradient and the Newton-Raphson method to self-consistently minimize the energy within local spin-density functional theory, thus to identify the ground state magnetic order of a finite cluster of atoms. The applicability of the new ab initio optimization method is demonstrated for Fe chains deposited on different metallic substrates. The optimized magnetic ground states of the Fe chains on Rh(111) are analyzed in details and a good comparison is found with those obtained from an extended Heisenberg model containing first principles based interaction parameters. Moreover, the effect of the different bilinear spin-spin interactions in the formation of the magnetic ground states is monitored. In case of Fe chains on Nb(110) spin-spiral configurations with opposite rotational sense are found as compared to previous spin-model results which hints on the importance of higher order chiral interactions. The wavelength of the spin-spiral states of Fe chains on Re(0001) was obtained in good agreement with scanning tunneling microscopy experiments.}, keywords = {DENSITY; Ab initio; FERROMAGNETISM; SKYRMION LATTICE; Magnetic nanoclusters}, year = {2022}, eissn = {1361-648X} } @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:31015490, title = {Metadynamics study of the temperature dependence of magnetic anisotropy and spin-reorientation transitions in ultrathin films}, url = {https://m2.mtmt.hu/api/publication/31015490}, author = {Nagyfalusi, Balázs and Udvardi, László and Szunyogh, László}, doi = {10.1103/PhysRevB.100.174429}, journal-iso = {PHYS REV B}, journal = {PHYSICAL REVIEW B}, volume = {100}, unique-id = {31015490}, issn = {2469-9950}, abstract = {We employ metadynamics simulations to calculate the free-energy landscape of thin ferromagnetic films and perform a systematic study of the temperature dependence of magnetic anisotropy and of the spin-reorientation transitions. By using a simple spin model we recover the well-known power-law behavior of the magnetic anisotropy energy against magnetization and present a rather detailed analysis of the spin-reorientation transitions in ultrathin films. Based on tensorial exchange interactions and anisotropy parameters derived from first-principles calculations, we perform simulations for Fe double layers deposited on Au(001) and W(110). In the case of Fe2W(110) our simulations display an out-of-plane to in-plane spin-reorientation transition in agreement with experiments.}, year = {2019}, eissn = {2469-9969}, orcid-numbers = {Nagyfalusi, Balázs/0000-0003-3875-2059} } @article{MTMT:30709889, title = {Magnetic structure of monatomic Fe chains on Re(0001): Emergence of chiral multispin interactions}, url = {https://m2.mtmt.hu/api/publication/30709889}, author = {Lászlóffy, András and Rózsa, Levente and Palotás, Krisztián and Udvardi, László and Szunyogh, László}, doi = {10.1103/PhysRevB.99.184430}, journal-iso = {PHYS REV B}, journal = {PHYSICAL REVIEW B}, volume = {99}, unique-id = {30709889}, issn = {2469-9950}, year = {2019}, eissn = {2469-9969}, orcid-numbers = {Rózsa, Levente/0000-0001-9456-5755; Palotás, Krisztián/0000-0002-1914-2901} } @article{MTMT:30708358, title = {Exchange interactions from a nonorthogonal basis set: From bulk ferromagnets to the magnetism in low-dimensional graphene systems}, url = {https://m2.mtmt.hu/api/publication/30708358}, author = {Oroszlány, László and Jaime, Ferrer and Deák, András and Udvardi, László and Szunyogh, László}, doi = {10.1103/PhysRevB.99.224412}, journal-iso = {PHYS REV B}, journal = {PHYSICAL REVIEW B}, volume = {99}, unique-id = {30708358}, issn = {2469-9950}, year = {2019}, eissn = {2469-9969}, orcid-numbers = {Oroszlány, László/0000-0001-5682-6424; Deák, András/0000-0002-3210-2947} } @article{MTMT:3368135, title = {Inducing skyrmions in ultrathin Fe films by hydrogen exposure}, url = {https://m2.mtmt.hu/api/publication/3368135}, author = {Hsu, P-J and Rózsa, Levente and Finco, A and Schmidt, L and Palotás, Krisztián and Vedmedenko, E and Udvardi, László and Szunyogh, László and Kubetzka, A and Von Bergmann, K and Wiesendanger, R}, doi = {10.1038/s41467-018-04015-z}, journal-iso = {NAT COMMUN}, journal = {NATURE COMMUNICATIONS}, volume = {9}, unique-id = {3368135}, issn = {2041-1723}, year = {2018}, eissn = {2041-1723}, orcid-numbers = {Rózsa, Levente/0000-0001-9456-5755; Palotás, Krisztián/0000-0002-1914-2901} } @article{MTMT:30357892, title = {First principles and metadynamics study of the spin-reorientation transition in Fe/Au(001) films}, url = {https://m2.mtmt.hu/api/publication/30357892}, author = {Nagyfalusi, Balázs and Udvardi, László and Szunyogh, László}, doi = {10.1088/1742-6596/903/1/012016}, journal-iso = {J PHYS CONF SER}, journal = {JOURNAL OF PHYSICS-CONFERENCE SERIES}, volume = {903}, unique-id = {30357892}, issn = {1742-6588}, abstract = {Based on first principles calculations, we investigate the magnetic anisotropy and spin reorientation transition (SRT) for Fe-n/Au(001) (n= 2, 3) films. The SRT occurs at three atomic layer of Fe in agreement with experiments due to competing on-site and two-site anisotropy. We also study the temperature dependence of the magnetic anisotropy energy (MAE) by means of metadynamics Monte Carlo simulations.}, keywords = {Physics, Applied; AU(100)}, year = {2017}, eissn = {1742-6596} }