Sperimagnetic structure

In these sperimagnetic structures, the subsystem magnetisations are reduced with respect to the collinear magnetic structure in the crystalline compounds. As a consequence, the saturation magnetostriction A.s is decreased. 

In these sperimagnetic structures, the subnetwork magnetisations are reduced. The influence of the exchange interactions and a random axial anisotropy on the average magnetic moment can be described using the Hamiltonian (Harris et al. 1973)... 

Equations (11) and (12) will be used to discuss the sperimagnetic structure of the magnetostrictive Tb-Co alloys in sect. 5.2. 

On the basis of the above consideration the magnetic structure of heavy R-T alloys in the interface region may have sperimagnetic features with random orientation of the local easy axes. For the material to show a macroscopic anisotropy, there must be an orientational coherence to these local anisotropy axes. The interfaces in R/T multilayers may have such desired structure to offer this orientational coherence. In sect. 3, the experimental evidence is presented and in sect. 4 a detailed model, which clearly shows such orientational coherence, is discussed. 

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