MAGNETIC SUSCEPTIBILITY STUDIES OF CUBIC LAVES PHASES SC(NI1-XCOX)2

Magnetic susceptibility studies have been made on the cubic C15(MgCu2-type) Laves phases Sc(Ni1 - xCox)2; the temperature dependences of susceptibility of the compounds ScNi2 and ScCo2 have been measured in the range 78 °-600 °K. The magnetic susceptibility of ScNi2 at room temperature is 1.4 μemu/g and decreases by about 20% between 78 °K and room temperature. Although the room temperature susceptibility of ScCo2 (12.6 μemu/g) is an order of magnitude larger than that of ScNi2, the form of the temperature dependence indicates that the cobalt does not carry a local magnetic moment. Experiments indicate that ScNi2 and ScCo2 may undergo severe surface damage by crushing at room temperature, sufficiently to yield metallic nickel or cobalt, respectively. The compounds are also extremely prone to oxidation above about 500 °K. Even at low pressures, atmospheric oxygen reacts with the scandium to leave free metallic nickel or cobalt, respectively. For comparison, the magnetic and structural properties of the cubic Laves phases RNi2 and RCo2 [where R represents Sc, Y, Ln (lanthanides), Ti and Zr]are reviewed. © 1969.