Garnets with dodecahedral rare earths and scandium, octahedral scandium, and tetrahedral iron. II. Magnetic studies

Abstract

Garnets with magnetic trivalent rare earth ions (Nd, Sm, Eu, Gd, Tb, Dy) filling all or nearly all dodecahedral sites while nonmagnetic Sc 3+ ions fill all octahedral sites and magnetic Fe 3+ ions fill all or nearly all tetrahedral sites have recently been reported by this laboratory. They afford an opportunity to seek magnetic interaction between dodecahedral rare earth ions and tetrahedral ferric ions in the absence of the additional interaction with octahedral iron which occurs in more conventional rare earth iron garnets such as {Gd 3}[Fe 2](Fe 3)O 12. For each composition, dependence of magnetization on temperature was measured between room temperature and that of liquid helium. Measurements were also made at liquid helium temperature of the dependence of magnetization on applied field with values up to 60.7 kOe. Low temperature results are in most cases ascribed to ferrimagnetic ordering but with canting of ion moments to explain why magnetic saturation has not been attained even with the maximum field applied. As is usually the case, the magnetic behavior of the Sm compound is quite different from that of the others and the possibilities of antiferromagnetism, paramagnetism, and metastable ferrimagnetism are discussed.