The magnetocrystalline anisotropy of the pseudobinary (Pr1-xNdx)2Fe14B compounds has been measured by using the singular point detection (SPD) technique. The measured temperature and composition dependence of the anisotropy field has been compared with the data obtained in CEF approximations using different sets of (Anm) parameters for Nd2Fe14B and Pr2Fe14B and by considering a linear combination of the anisotropy in the mixed system. The comparison is made by calculating the anisotropy constants, then the anisotropy field values, starting from the (Anm) parameters. Experimental and calculated data concerning the occurrence of spin reorientation transition (SRT) and of type 1 and type 2 first-order magnetisation processes (FOMP) as a function of composition have also been compared.

A comparative study of the saturation magnetization, Curie temperature, and magnetocrystalline anisotropy in several rhombohedral and hexagonal Y-Co compounds was done. The considered phases YCo3, Y2Co7, Y5Co19 (rhombohedrals), YCo5+z, and Y2Co17 (hexagonals) are all derived from the hexagonal CaCu5 unit. The variation of the magnetic properties in the different compounds was found to be strongly correlated to the cobalt content. In particular the Co sublattice anisotropy varies linearly with the Co content in the phases, while it seems to be not affected by structural changes (rhombohedral-hexagonal). The highest anisotropy of Co was found in YCo5, every modification of the CaCu5 cell resulting in a weakening of the overall axial anisotropy. An evaluation of the strength of the Co anisotropy in the 2c, 3g, and dumbbell sites was done using a phenomenological model.

The compounds REFe12−xVx(RE=Y,Er,Tb) having the tetragonal crystal structure of ThMn12 exist in the composition range 1.5≤x≤4. The dependence of the magnetic properties on the vanadium content were investigated in order to evidence and study any influence of vanadium on the magnetic anisotropy of both iron and RE sublattices and, as a consequence, on the magnetic phase diagram of these systems. The influence of vanadium was found to be remarkable on Tc, Ms, and Fe anisotropy, which decrease in all the compounds with increasing V content. However the largest effect was observed on the RE anisotropy and particularly in TbFeV, where the anisotropy of the Tb sublattice is turned from planar to axial by increasing the vanadium concentration, thus giving rise to strong effects on the macroscopic magnetic behavior and on the magnetic phase diagram of these systems. The large variation of the spin reorientation transition temperature Tsr, observed by varying V content on both ErFeV and TbFeV, can justify the spread in the literature data which could be attributed to small not considered stoichiometry differences with respect to the nominal composition.

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Effect of vanadium on the RE and Fe sublattice anisotropies in some REFe12x V x (RE=Y,Er,Tb) tetragonal compounds Smallangle neutron scattering in spin reorientation transitions of (Er x Nd1x )2Fe14B hard pseudoternaries