Millev, Y. T., FĂ¤hnle, M.

Anomalous behaviour of the second constant of magnetic single-ion anisotropy as a function of magnetization and temperature

Journal of Magnetism and Magnetic Materials

**163**, (3),pp L264-L266 (1996)

An exhaustive study is carried out for the determination of the possible types of variation of the second single-ion anisotropy constant K

_{2}. Three types are found and quantified, two of which are anomalous and unknown by now. While they both exhibit a non-monotonic variation with a local extremum between zero and the Curie temperature, one of them is additionally characterized by a zero point and, consequently, by a change of sign of K_{2}. The value of a unique parameter (the ratio K^{0}_{3}/K^{02}) is vital for the classification of the above types, whereby the value of the first anisotropy constant is completely irrelevant. The dependences for the variation of K_{2}are generated with the help of a new parametric method.ki-1996-a03