TY  - JOUR
AU  - Lászlóffy, András
AU  - Rózsa, Levente
AU  - Palotás, Krisztián
AU  - Udvardi, László
AU  - Szunyogh, László
TI  - Magnetic structure of monatomic Fe chains on Re(0001): Emergence of chiral multispin interactions
JF  - PHYSICAL REVIEW B
J2  - PHYS REV B
VL  - 99
PY  - 2019
IS  - 18
PG  - 13
SN  - 2469-9950
DO  - 10.1103/PhysRevB.99.184430
UR  - https://m2.mtmt.hu/api/publication/30709889
ID  - 30709889
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Szilva, Attila
AU  - Costa, M
AU  - Bergman, A
AU  - Szunyogh, László
AU  - Nordstrom, L
AU  - Eriksson, O
TI  - Interatomic Exchange Interactions for Finite-Temperature Magnetism and Nonequilibrium Spin Dynamics
JF  - PHYSICAL REVIEW LETTERS
J2  - PHYS REV LETT
VL  - 111
PY  - 2013
IS  - 12
PG  - 5
SN  - 0031-9007
DO  - 10.1103/PhysRevLett.111.127204
UR  - https://m2.mtmt.hu/api/publication/2695314
ID  - 2695314
AB  - We derive ab inito exchange parameters for general noncollinear magnetic configurations, in terms of a multiple scattering formalism. We show that the general exchange formula has an anisotropiclike term even in the absence of spin-orbit coupling, and that this term is large, for instance, for collinear configuration in bcc Fe, whereas for fcc Ni it is quite small. We demonstrate that keeping this term leads to what one should consider a biquadratic effective spin Hamiltonian even in the case of collinear arrangement. In noncollinear systems this term results in new tensor elements that are important for exchange interactions at finite temperatures, but they have less importance at low temperature. To illustrate our results in practice, we calculate for bcc Fe magnon spectra obtained from configuration-dependent exchange parameters, where the configurations are determined by finite-temperature effects. Our theory results in the same quantitative results as the finite-temperature neutron scattering experiments.
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Udvardi, László
AU  - Szunyogh, László
TI  - Chiral Asymmetry of the Spin-Wave Spectra in Ultrathin Magnetic Films
JF  - PHYSICAL REVIEW LETTERS
J2  - PHYS REV LETT
VL  - 102
PY  - 2009
IS  - 20
PG  - 4
SN  - 0031-9007
DO  - 10.1103/PhysRevLett.102.207204
UR  - https://m2.mtmt.hu/api/publication/117092
ID  - 117092
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Antal, A
AU  - Lazarovits, Bence
AU  - Udvardi, László
AU  - Szunyogh, László
AU  - Ujfalussy, Balázs
AU  - Weinberger, P
TI  - First-principles calculations of spin interactions and the magnetic ground states of Cr trimers on Au(111)
JF  - PHYSICAL REVIEW B
J2  - PHYS REV B
VL  - 77
PY  - 2008
IS  - 17
PG  - 8
SN  - 2469-9950
DO  - 10.1103/PhysRevB.77.174429
UR  - https://m2.mtmt.hu/api/publication/117126
ID  - 117126
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Udvardi, László
AU  - Szunyogh, László
AU  - Palotás, Krisztián
AU  - Weinberger, P
TI  - First-principles relativistic study of spin waves in thin magnetic films
JF  - PHYSICAL REVIEW B
J2  - PHYS REV B
VL  - 68
PY  - 2003
IS  - 10
PG  - 11
SN  - 2469-9950
DO  - 10.1103/PhysRevB.68.104436
UR  - https://m2.mtmt.hu/api/publication/2633165
ID  - 2633165
AB  - In order to study spin-wave excitations of itinerant ferromagnets a relativistic first-principles method based on the adiabatic approach is presented. The derivatives of the free energy up to second order with respect of the polar and azimuthal angles are derived within the framework of the magnetic force theorem and the fully relativistic Korringa-Kohn-Rostoker method. Exchange and spin-orbit coupling are thus incorporated on equal footing in the Hamiltonian. Furthermore, a
detailed comparison to classical spin Hamiltonians is given and it is shown that the magnetocrystalline anisotropy energy contains contributions from both the on-site anisotropy and the off-site exchange coupling terms. The method is applied to an Fe monolayer on Cu(001) and Au(001) surfaces and for a Co monolayer on Cu(001). The calculations provide with the gap at zero wave number due to the spin-orbit coupling and uniaxial anisotropy energies in good agreement with the results of the band energy difference method. It is pointed out that the terms in the spin-wave Hamiltonian related to the mixed partial derivatives of the free energy, absent within a nonrelativistic
description, introduce an asymmetry in the magnon spectrum with respect to two in-plane easy axes. Moreover, in the case of an in-plane magnetized system the long-wavelength magnons are elliptically polarized due to the difference of the second-order uniaxial and fourth-order in-plane magnetic anisotropy.
LA  - English
DB  - MTMT
ER  -