FERROMAGNETIC SUPERCONDUCTORS - EFFECT OF DISORDER ON THE COEXISTENCE PHASE IN ERRH4B4 AND PSEUDOTERNARY SYSTEMS

The asperomagnetic ordering model with a randomly oriented 'easy axis' in the basal plane provides a natural explanation of the unusual magnetic properties of ErRh//4B//4, including the different results of Moessbauer and neutron diffraction measurements of the magnetic moment in the normal low temperature magnetic phase (FN phase) as well as anomalies in the magnetic ordering at the transition from the nonmagnetic superconducting phase (S phase) to the FN phase. Here the small intensities of satellites and the simultaneous appearance of ferromagnetic peaks and satellites are explained in terms of the destruction of inhomogeneous magnetic structure in the coexistence phase due to disorder in the main part of the sample. The effect of disorder on the coexistence state in pseudoternary compounds is also considered.