Crystal Chemistry and Competing Magnetic Exchange Interactions in Oxide Garnets and Spinels

In this contribution, we review the crystal chemistry and magnetic exchange pathways in atomically well-ordered oxide garnets and spinels. While superficially the topologies of these two structures appear quite different, both are capable of accommodating a large number of magnetic elements from across the periodic table within multiple coordination environments, making them ideal for identifying new design principles. We present a comparison of the crystal chemistry for the two structures and an overview of the various magnetic properties that have been observed when one or more magnetic ions occupy the individual sublattices. We identify that the large number of degenerate superexchange pathways between each sublattice in either structure plays a critical role in producing novel magnetic behavior.