Site-selective couplings in x-ray-detected magnetic resonance spectra of rare-earth-substituted yttrium iron garnets

Abstract

Site-selective x-ray detected magnetic resonance (XDMR) spectra were recorded in transverse detection geometry on two iron garnet thin films grown by liquid phase epitaxy (LPE) on oriented gadolinium gallium garnet (GGG) substrates: whereas the stoichiometry of the first film corresponded to pure yttrium iron garnet (1 = YIG) used as reference, yttrium was partly substituted with lanthanum and lutetium in the second film (2 = La-Lu-YIG). Surprisingly, the XDMR spectra of film 2 recorded at either the Fe K-edge or the La L 3-edge revealed well-resolved structures that had fairly different relative intensity depending on whether we probed the tetrahedral (S 4) sites of iron or the dodecahedral (D 2) sites of lanthanum. The narrow XDMR lines measured at the Fe K-edge also contrast with the broad, foldover distorted lineshapes of the ferrimagnetic resonance spectra measured in the same scan. Further XDMR experiments were carried out with a thin, disc-shaped, single crystal of gadolinium iron garnet (3 = GdIG). At temperatures slightly above the gadolinium ordering temperature (T > T B = 69 K), the Gd L 2-edge XDMR. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.