TY - JOUR
T1 - Surface spin waves and surface spin arrangements in helical magnets
AU - Harada, I.
AU - Nagai, O.
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 1978
Y1 - 1978
N2 - In order to investigate the nature of the spin arrangement in the surface of a semi-infinite helical magnet, we calculate both the surface spin-wave frequency spectra and the classical spin-ordering energies. We present detailed calculations for a (100) surface of a body-centered tetragonal lattice with nearest neighbor and next nearest neighbor exchange interactions (J1 and J2, which are both negative). The possibility that the exchange interactions in the surface (Js2) may differ from those in the bulk (J2) is taken into account. We find the following: In the case 0≳Js2≳J2, the surface spin-wave frequencies are real and positive, and hence the uniform helical spin arrangement is stable. On the other hand, in the case Js 2<J2, there exist soft surface spin-wave modes, which indicate that the uniform helical spin arrangement is not stable. In the latter case, it is shown that a nonuniform spin arrangement, characterized by a rearrangement of spins in the surface, has a lower classical spin-ordering energy than the uniform state and hence is stable.
AB - In order to investigate the nature of the spin arrangement in the surface of a semi-infinite helical magnet, we calculate both the surface spin-wave frequency spectra and the classical spin-ordering energies. We present detailed calculations for a (100) surface of a body-centered tetragonal lattice with nearest neighbor and next nearest neighbor exchange interactions (J1 and J2, which are both negative). The possibility that the exchange interactions in the surface (Js2) may differ from those in the bulk (J2) is taken into account. We find the following: In the case 0≳Js2≳J2, the surface spin-wave frequencies are real and positive, and hence the uniform helical spin arrangement is stable. On the other hand, in the case Js 2<J2, there exist soft surface spin-wave modes, which indicate that the uniform helical spin arrangement is not stable. In the latter case, it is shown that a nonuniform spin arrangement, characterized by a rearrangement of spins in the surface, has a lower classical spin-ordering energy than the uniform state and hence is stable.
UR - http://www.scopus.com/inward/record.url?scp=36749109294&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=36749109294&partnerID=8YFLogxK
U2 - 10.1063/1.324712
DO - 10.1063/1.324712
M3 - Article
AN - SCOPUS:36749109294
VL - 49
SP - 2144
EP - 2146
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 3
ER -