| Popis: |
The principal directions, the principal values of the ∥g∥ tensor, and the exchange parameters are determined from magnetic resonance experiments performed at low temperature ( T = 1.5 K T N ), in a large range of frequencies (20 MHz–310 GHz) and in a d.c. magnetic field up to 56 KOe. We show that the principal directions OX and OZ (respectively easy and hard magnetization axes) are in the mirror plane aa ′ c ; OX is titled by 3.5° from c towards a ′, OY is the twofold symmetry axis. The principal values are stationary close to the principal directions and we find: g OX ≈ g c = 4.8, g OY = g b = 4.6 and g OZ ≈ g a ′ = 2.8. From high temperature magnetic resonance experiments at T = 4.2 K > T N , we obtain g ( H ∥ c ) = 4 and g ( H ∥ b ) = 4.25. The discrepancy with former values is attributed to the exchange anisotropy fields. |
