Anisotropic susceptibilities of thin ferromagnetic films within many-body Green function theory: single-ion anisotropy versus exchange anisotropy

Abstract

Abstract. We compare transverse and parallel static susceptibilities of in-plane uniaxial anisotropic ferromagnetic Heisenberg films calculated in the framework of many-body Green's function theory using single-ion anisotropies with the previously investigated case of exchange anisotropies. On the basis of the calculated observables (easy and hard axes magnetizations and susceptibilities) no significant differences are found, i.e. it is not possible to propose an experiment that might decide which kind of anisotropy is acting in an actual ferromagnetic film.

Anisotropy effects on the magnetic excitations of a ferromagnetic monolayer below and above the Curie temperature

“…Recently, a number of Green's function theories were proposed by different authors 14,15,16,17,18 to treat the problem of the field-induced transition in ultrathin ferromagnetic films. A thorough discussion of the limits of the approximations used in Ref.…”

“…18. It is worth noticing that other Green's function approaches 14,15,16 were not able to recover such a feature, either. So far, in our calculations, the problem of the kinematic consistency of the magnetic excitations was neglected since the naïve RPA decoupling was performed also for the Green's functions coming from the anisotropy term in the Hamiltonian.…”

Thermodynamic properties of the Ising and Heisenberg S = 1 ferromagnet with biquadratic exchange and uniaxial anisotropy

“…Since the pioneering work of Chen and Levy (1973) [1], there have been a lot of studies dedicated to the subject trying to generalize these results in several directions. One approach was to use more sophisticated techniques like Green's functions (GF), as done in [6][7][8][9][10][11][12]. Another direction was to study the influence of surfaces on the magnetic structure [13][14][15][16], while several studies were dedicated to the influence of anisotropy [17,18].…”

Magnetic Reorientation in the Antiferromagnetic Bi-layer: Exchange Anisotropy Versus Single-Ion Anisotropy

“…This magnetic reorientation has been shown to be a consequence of the competition between the perpendicular anisotropy and dipolar interaction (or an external transverse magnetic field) [1]. In [2,3], the Green function theory was employed to V. Ilkovič vilko@theor.jinr.ru 1 Bogoliubov Laboratory of Theoretical Physics, JINR, 141980, Dubna, Moscow region, Russia 2 Present address: Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 43, 040 01 Košice, Slovakia calculate the easy and hard axis magnetizations and susceptibilities of ferromagnetic thin films with the exchange and single-ion anisotropy. Only one value of the strength of the exchange and single-ion anisotropy, respectively, was used in the calculation.…”