Electron-Spin Polarization at Single-Crystalline Cr and Ni Surfaces Determined with Electron-Capture Spectroscopy
The spin polarization P of electrons at Cr and Ni surfaces is measured with electron-capture spectroscopy. With use of one-electron capture at magnetized Cr(100)-c(2×2) surfaces at 293 K (TN=310 K), P values up to -18% are found revealing ferromagnetic order at this surface. Utilizing two-electron capture at demagnetized Ni surfaces we find at 293 K (TC=631 K) |P|=94% for Ni(110), |P|=72% for Ni(100), |P|=47% for Ni(111), and |P|=14% for Ni(120). There is evidence that "local" ferromagnetic order at Ni surfaces exists even at 2TC.