Garnets, magnetic rare-earth

Ca is replaced by a rare-earth element, resulting in a distorted perovskite stmcture, which is essentially orthorhombic. Orthoferrites, studied extensively in the early 1970s as potential data storage materials based on magnetic bubble domains (10), have been largely replaced by the garnet materials (see... 

Although the garnet compositions used in memories contain rare earths, the total rare earth use in magnetic films is not sufficient to make much impact on the rare earth market. The use of gadolinium oxide in substrate crystals is another matter. It has been estimated that by 1990 the annual use of Gd203 for GGG substrates will reach 40 metric tons, about twice the present rate (21). 

The development of the bubble domain memory has been remarkable in that since the discovery of the growth induced anisotropy in garnets, problems connected with materials have been relatively few and not too difficult to solve. A major reason is that the different sizes and magnetic properties of the rare earths offer a wide range of choices for the materials designer. 

Rare earth substituted garnet films for magnetic bubble memory applications... 

Soft magnets Transformer cores [(Zn, M)Fe203, with M = Mn, Co, Mg] magnetic tapes (rare-earth garnets)... 

The general formula of magnetic garnets,is P3Q2R3O12 or 3Mc203 5Fe203, where Me is typically yttrium but can also be other rare earth ions. The basic crystal structure is cubic with an octahedron, a tetrahedron. 

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