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Full-Text Articles in Physics
Determination Of Crystal-Field Parameters Of Sm2Fe17N3 And Sm2Fe17C3, S. Wirth, M. Wolf, K.H. Muller, Ralph Skomski, S. Brennan, J.M.D. Coey
Determination Of Crystal-Field Parameters Of Sm2Fe17N3 And Sm2Fe17C3, S. Wirth, M. Wolf, K.H. Muller, Ralph Skomski, S. Brennan, J.M.D. Coey
Ralph Skomski Publications
The crystal-field parameters A20 and A40 were determined from the magnetocrystalline anisotropy constants K1 and K2 in a linear approximation for Sm2Fe17Zx (Z = N, C) compounds. For the materials investigated, the values of Iη0 are calculated in two ways: i) from the Kί at zero temperature and ii) from the temperature dependence of the Kί. Both methods give equivalent results. The value A20≈-400 Ka0-2 has been obtained which corresponds to an inverse THOMAS-FERMI screening length q≈2.3 Å-1 calculated within the framework …
Is There Spin-Glass Exchange In Ultrathin Fe(110) Films ?, Ralph Skomski, D. Sander, Axel Enders, J. Kirschner
Is There Spin-Glass Exchange In Ultrathin Fe(110) Films ?, Ralph Skomski, D. Sander, Axel Enders, J. Kirschner
Ralph Skomski Publications
The magnetism of sesquilayer bcc iron films on W(110) is investigated. Coercivity data and theoretical calculations that the freezing of the magnetization at low temperatures reflects exchange-dominated domain-wall pinning rather than superparamagnetic spin-glass behavior.
Film Stress And Domain Wall Pinning In Sesquilayer Iron Films On W(110), D. Sander, Ralph Skomski, C. Schmidthals, Axel Enders, J. Kirschner
Film Stress And Domain Wall Pinning In Sesquilayer Iron Films On W(110), D. Sander, Ralph Skomski, C. Schmidthals, Axel Enders, J. Kirschner
Ralph Skomski Publications
We present an in situ investigation of the correlation between elastic and magnetic properties of monolayer iron films on W(110). Sesquilayers, consisting of two-monolayer patches on a nearly ideal monolayer film, exhibit anomalous elastic properties and a strikingly high in-plane coercivity of order 0.3 T. The sesquilayer coercivity maximum is explained by a novel domain wall pinning mechanism, based on an enhanced exchange interaction in the two monolayer thick patches. This rather unique behavior is restricted to (110) surfaces but does not occur on (100) and (111) thin films.
An Effective-Viscosity Description Of Domain-Wall Motion In Magnetic Thin Films With Perpendicular Anisotropy, Ralph Skomski, J. Giergiel, J. Kirschner
An Effective-Viscosity Description Of Domain-Wall Motion In Magnetic Thin Films With Perpendicular Anisotropy, Ralph Skomski, J. Giergiel, J. Kirschner
Ralph Skomski Publications
The expansion of magnetic domains in thin films with perpendicular anisotropy is investigated. To determine the domain-wall velocity as a function of the applied magnetic field a self-=consistent magnetic-viscosity approach is used. The main predictions of the theory are a linear behavior\r in the limit of moderately strong fields, a quasi-exponential behavior for fields close to the propagation field, and a negative velocity for very small and negative fields. The predictions of the theory are compatible with domain-wall investigations on Au/Co/Au sandwiches.
High Coercive Field And Film Stress For Epitaxial Monolayers Of Fe On W(110), D. Sander, Axel Enders, Ralph Skomski, J. Kirschner
High Coercive Field And Film Stress For Epitaxial Monolayers Of Fe On W(110), D. Sander, Axel Enders, Ralph Skomski, J. Kirschner
Ralph Skomski Publications
Elastic and magnetic properties of ultra-thin iron films on tungsten(110) are investigated. In situ film stress measurements during growth show stress values of 25 GPa per deposited monolayer. Our experiments indicate that the tremendous film stress triggers the formation of a misfit dislocation network at a coverage of 1.5 monolayers. The effect of the film stress and its spatial variation on the magnetic behavior are discussed. We find an high coercivity of order 0.3 T for 1.5 monolayer thick films. A model is presented that explains the high coercivity in terms of strong domain wall pinning.
The Itinerant Limit Of Metallic Anisotropy, Ralph Skomski
The Itinerant Limit Of Metallic Anisotropy, Ralph Skomski
Ralph Skomski Publications
The anisotropy contribution of itinerant electrons confined to a quantum-well potential is calculated and compared with the quasi-ionic contribution due to virtually bound electrons. The easy magnetization direction of the non-L-S quantum-well electrons lies in the plane, and the magnitude of the anisotropy, maximally of order 10 J/m3, is too weak to explain anisotropies encountered in practice. This means that itinerant 3d anisotropy in bulk materials and thin films is associated with Hund's rules-type ionic Contributions.