HUBBARD SPLITTING AND ELECTRON CORRELATION IN THE FERROMAGNETIC METALCRO2

We have studied the electronic structure of CrO2 by photoemission spec troscopy and specific heat measurements. The Cr 3d band shows a splitt ing into the upper and lower Hubbard bands with a small but finite den sity of states at the Fermi level, consistent with its metallic behavi or. The small renormalization factor (z similar to 0.1 much less than 1) signifies strong electron correlation, but is still large compared with many 3d transition-metal oxides.