Temperature dependence of the hyperfine parameters on FeO(111) surfaces

Asakawa, Kanta*; Kawauchi, Taizo*; Fukutani, Katsuyuki

The Verwey transition on FeO(111) surface was investigated using nuclear resonant X-ray scattering (NRS). Measurements were conducted below (85K) and above (297 and 500K) the Verwey transition temperature. The internal magnetic field estimated from the NRS frequency spectra agreed with that of bulk FeO at all measured temperatures. A clear change in the intensity ratio of the two peaks in the frequency spectra was observed across the Verwey transition. The results indicate that despite the presence of the peculiar surface electronic states which makes the changes in the electronic properties across the Verwey transition temperature blurred, the hyperfine parameters of the (111) surface show a clear change across the Verwey transition temperature.