-
本文讨论二价铁对铁氧体的铁磁共振线宽的影响。由于在尖晶石型铁氧体中,二价铁的基态是轨道单态,晶场的直接效应很小。二价铁对铁磁共振性质有显著影响的原因是各向异性交换作用引起二价铁磁矩不与总磁矩平行,因而使得文献[1]中所述的纵分支对共振性质起作用。我们推广文献[1]中的方法,使之适用于强交换耦合体系,并用之计算了二价铁对共振线宽的影响。计算表明,体系间的交换耦合的强弱对线宽的影响很小。对含二价铁反型尖晶石型铁氧体算得的结果解释了[100]方向线宽随温度的变化不出现极大,而在其他方向则出现极大的现象。导出的线宽的各向异性也与实验相符。The influence of Fe2+ on the ferrimagnetic resonance properties of nickel ferrites was discussed. Since the ground state of Fe2+ in spinels is a singlet, the crystal field only slightly affects the motion of the spin magnetic moment of Fe2+. It was pointed out that due to the anisotropy of the exchange interaction between Fe2+ and Fe3+ or Ni2+ situated at the octahedral position, the longitudinal branch might play the major role in the relaxation process of nickel ferrites.The method used in Ref. [1] was extended to treat the strong exchange coupled system. It was confirmed that usually the expression for the line width coincides with that of the case of a weakly coupled system.Under the light of a reasonable model of anisotropic exchange interaction the experimental fact that the line width goes through a maximum at a definite temperature along all crystal directions except [001], was satisfactorily explained. The theoretical expression obtained for the anisotropy of the line width agrees with the experimental results.
[1] -
[1]
计量
- 文章访问数: 7791
- PDF下载量: 433
- 被引次数: 0