Influence of magnetocrystalline anisotropy effects on the magnetic isotherms of hexagonal Laves phase materials in the system Zr(Fe, Al)2

The
M(H,T)
isotherms of the hexagonal Laves phase materials Zr(Fe
x
Al
1-x
)
2
(
0.56 \leq x \leq 0.74
) were obtained experimentally in fields up to 72 kG and at a temperature 4.2 K. The resulting Arrott plots (M
²
versus H/M) show downturns from the linear behavior characteristic of weak itinerant ferromagnets in fields in the range H/M about 0.5-1.0 kG/emu/g. These deviations arise, at least in part, from magnetocrystalline anisotropy effects. The relevant anisotropy fields were measured directly using the singular point detection method and indirectly by using a theoretical analysis based on domain rotation effects. From the differences of the observed and calculated Arrott plots and from these anisotropy fields conclusions regarding other causes of the anomaly may be drawn.