Electron-Spin-Resonance Absorption Spectrum of Platinum in Yttrium Aluminum Garnet

An electron-spin-resonance absorption spectrum taken at 3-cm wavelength and attributed to trivalent platinum (5d⁷,t⁶e) at octahedral sites in yttrium aluminum garnet has been observed at temperatures below 120^∘{}K. The spectrum is described by S=1/2 and I=1/2 (due to the 34% abundant ¹⁹⁵Pt). There are 24 magnetically inequivalent orientations of the platinum ion per unit cell arising from what is believed to be static Jahn-Teller distortions at each of the eight inequivalent octahedral sites. The g and A tensors are orthorhombic with principal components gᵢ=1.962, gⱼ=2.361, gₖ=2.424 and Aₗ=99 Oe, Aₘ=88 Oe, and Aₙ=30 Oe. The two tensors are not diagonal in the same coordinate system and their orientations with respect to the garnet cubic directions is discussed.