Abstract
Magnetic properties of single crystals of CrBr3 have been measured with a magnetic balance and also with a torque magnetometer. The ferromagnetic Curie point has been found to be 37°K from the temperature dependences of magnetization and of torque. Based on the data of the magnetic susceptibility above the Curie point, the paramagnetic Curie point θp, Curie constant CM and the effective Bohr magneton number have been determined to be 47°K, 1.84 and 3.85 μB respectively. From the saturation magnetization at 42°K, the moment of chromium ion is estimated to be 3 μB, coinciding with the spin moment obtained from the susceptibility measurement above the Curie temperature. Direction of easy magnetization lies along the c-axis of the hexagonal lattice, and the second order and the fourth order anisotropy constants are estimated to be K1=−5.08×105 and K2=0.65×105 erg/cc respectively. In the present results, there is found a small deviation in the torque curves from simple sinusoidal form, L=Ksin2θ, which is discussed on the basis of the higher order term of magnetic anisotropy in the high field strength range and also of the domain-theoretical consideration in the low field strength range.
