Polaronic absorption in uncompensated Ca_X:YIG Available to Purchase

In charge uncompensated Ca_X:YIG, magnetic anomalies and a photoinduced absorption spectrum have been reported. The temperature dependence of the photoinduced peak observed at 1.85 eV (width 0.5 eV) has the same temperature dependence as the low‐temperature anomalies observed in the magnetizations. A model to explain the low‐temperature magnetic anomaly assumes that a non‐S state iron ion, Fe⁴⁺, is created in the tetrahedral site that is ferromagnetically coupled to the octahedral Fe³⁺ ion. An alternative model recently proposed assumes that O⁻ ions are formed which would influence the magnetic properties in similar fashion. The broad nature of the absorption at 1.85 eV is characteristic of a resonant transition of photocarriers. In this paper the absorption band is discussed in terms of a polaron hopping model.