DETERMINATION OF THE FIRST ANISOTROPY CONSTANT OF UNIAXIAL ANISOTROPIC MATERIAL FROM INITIAL SUSCEPTIBILITY OF MAGNETIZATION HARD DIRECTION

A method to calculate the first anisotropy constant of a uniaxial anis otropy system from the initial susceptibility of magnetization hard di rection have been studied. The formulas for single crystal and magneti cally aligned powder based on rigid coupled magnetization model or two sublattice magnetization model have been derived and applied to deter mine the anisotropy constant of RE2Fe14B (RE = Ce, Pr, Gd, Tb, Dy) com pounds. From the susceptibility of single crystals, the first anisotro py constants of a rare-earth sublattice of an RE2Fe14B-type compound h ave been calculated to be K-1Pr = 5200 J/kg, K-1Tb = 4500 J/kg and K-1 Dy = 1700 J/kg, and they are found to be 15-45 times stronger than the anisotropy of Fe-sublattice. (C) 1998 Elsevier Science B.V. All right s reserved.