Evidence of negative spin polarization in ferromagneticSr2FeMoO6as observed in a magnetic Compton profile study

Abstract

The spin-polarized electron momentum distribution [magnetic Compton profile (MCP)] of ferromagnetic ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6}$ has been measured, using the magnetic Compton scattering technique, at temperatures $10\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and $300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, for the [100] and [110] crystallographic directions. The experimental results have been compared with results from electronic structure calculations performed utilizing the full potential linearized augmented plane-wave method. The calculated results clearly show that only down-spin states contribute to the ${E}_{\mathrm{F}}$ intensity (half metallic character). The experimental observations clearly show evidence for the existence of negative spin polarization that arises from down-spin bands. We have observed the change in the MCP, which arises from the band spin fluctuation, between the low temperature $10\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and high temperature $300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$.