Morphotropic phase boundary in pseudo-binary Ferromagnetic Tb1−xGdxFe2 system

The structure and magnetic properties of ferromagnetic Tb_1-xGdxFe₂ system have been studied through the morphotropic phase boundary (MPB), a phase boundary between two ferroic phases of different crystal symmetry. Morphotropic phase boundary (MPB) has been studied extensively for its extraordinary enhancement effect in ferroelectrics. Based on same mechanism, we have designed a pseudobinary ferromagnetic system Tb_1-xGdxFe₂, of which the near-MPB composition Tb_1-xGdxFe₂ shows maximum magnetization under small field, and meanwhile dramatically the low magnetostriction. With synchrotron x-ray diffractometry, the crystal structure of TbFe₂-rich compositions is detected to be rhombohedral and that of GdFe₂-rich compositions is tetragonal below their curie temperatures. The near MPB composition Tb_0.1Gd_0.9Fe₂, shows the maximum magnetization among all available compositions and superposition of magnetostriction behavior of R and T phases. To find MPB phenomena in ferromagnets may provide a new route to design functional materials in other ferroic MPB systems.