THE MAGNETIC PHASE-TRANSITION IN FE14ND2B SINGLE-CRYSTALS

The magnetic phase transition of a Fe14Nd2B single crystal is investigated with respect to various angles PSI between the easy axis and the direction of the applied magnetic field. The Curie temperature, T(c), and the critical exponents beta, gamma, gamma' and delta are determined by several methods: modified Arrott plots, the method of Kouvel and Fisher, scaling plots and 1n(J) versus 1n(mu-0H) plots. The analysis of the isotherms of the easy direction leads to critical exponents which agree neither with the 3-dimensional Heisenberg model nor the 3-dimensional Ising model. Furthermore it turns out that the analysis of the isotherms with orientations different from the easy direction yields a significant dependence of the "critical exponents" as well as of the "Curie temperature" upon the angle PSI.