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Emergence and inflection angles in the configurational dependence of interface bilayer spin wave energies
Author(s) -
Puszkarski H.,
Józefowicz R.,
Kolodziejczak B.,
Akjouj A.,
DjafariRouhani B.,
Dobrzynski L.
Publication year - 1996
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221940229
Subject(s) - brillouin zone , condensed matter physics , inflection point , bilayer , anisotropy , perpendicular , brillouin spectroscopy , plane (geometry) , isotropy , physics , optics , materials science , geometry , chemistry , brillouin scattering , mathematics , biochemistry , membrane , optical fiber
For the two interface cubic cuts b.c.c. (110) and f.c.c. (111) we consider the existence regions of interface spin waves (ISWs) in a ferromagnetic bilayer film on the two‐dimensional Brillouin zone (BZ) concerning their size and shape versus the respective interface related parameters (interface exchange coupling and intrinsic interface anisotropy), applying the approximation of a very thick bilayer film and the method of Brillouin zone mapping (BZM). We emphasize the effect exerted on the BZM by varying (in the plane perpendicular to the film) the configuration angle ϑ of the film magnetization with respect to the film normal. We predict the existence of (at most two) critical angles ϑ E at which the ISWs emerge. The emergence angles are functions of the in‐plane wave vector k ∥ of ISW propagation along the interface. We show that the ISW energy varies monotonously with variations of the angle ϑ attaining zero slope on the edges of the interval of ϑ variability (implying simultaneously the existence of a characteristic point of inflection inside the interval). We prove that the nature of the monotonicity is determined unequivocally by the type of the intrinsic interface anisotropy, namely: the ISW energy grows (decreases) monotonously with the angle ϑ if the interface anisotropy is of easy‐plane (easy‐axis) type. Moreover, we discuss the effects due to the presence of critical and inflection angles with a view to their exploitation in experimental measurements.