MAGNETIC, TRANSPORT, AND THERMAL-PROPERTIES OF FERROMAGNETIC EUB6

Magnetic measurements on Al-flux grown EuB6 crystals show that this material orders ferromagnetically with a transition temperature T c=13.7 K. The effective moment derived from paramagnetic susceptibility measurements gives μeff=7.76 μB, and the saturation magnetization extrapolated to 0 K is within 10% of the theoretical value of 7 μB expected for Eu+2. The magnetic order, however, cannot be that of a simple colinear ferromagnet because the magnetic specific heat in zero applied magnetic field shows a broad maximum centered about 9 K rather than the expected λ-like anomaly at 13.7 K. Finally, transport measurements suggest that EuB6 is an intrinsic semimental.