We report EPR and magnetic susceptability measurements in single crystals of Cd1-xMnxSe as a function of concentration and temperature. The data indicate that there is a critical concentration x≈0.22 which we identify with the percolation critical point xc. © 1980.

The magnetic susceptibility χ of nickel diglycine dihydrate has been measured between 0.6 and 120 K. The high-temperature data were taken in powder and follow a Curie law behavior with μeff = 3.189 μB and an antiferromagnetic Curie temperature TC = 2.47 K. At low temperatures the χ vs temperature curves for powder and oriented single crystals deviate from the Curie law; they show a maximum χ at about 2.21 K and an abrupt decrease at lower temperatures. The observed behavior of χ for nickel diglycine dihydrate indicates dominating antiferromagnetic interactions between Ni ions. A phase transition to an antiferromagnetic phase occurs below 2.2 K.

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.