Acquisition of thermoremanent magnetization in weak magnetic fields
Acquisition of thermoremanent magnetization in weak magnetic fields
复制标题
弱磁场中热剩磁的获取
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
K. Fabian
中科院分区：
文献类型：
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作者：
K. Fabian
摘要
借助于弱场热剩余磁化(TRM)的唯象模型，可以很好地近似再现TRM和部分TRM(PTRM)的复杂行为。该模型将样品描述为统计上相互独立的磁化元素的集合，每个磁化元素具有确定的阻塞和确定的解除阻塞温度。此外，对于弱场，对于每个磁化元素，假定剩磁与外加磁场成线性关系。这些假设足以推导出不同类型的pTRM之间的实验发现的一级关系。在考虑平均场相互作用的情况下，由该模型得到了控制多域材料冷却过程的运动学方程。现象学模型由两种物理方法支持。利用磁相理论，来自唯象模型的运动学方程中的系数可以物理地解释为各向同性的单轴MD粒子系综。对热平衡态的严格微磁分析证明了平衡剩磁作为弱外加磁场的函数的线性。统计论证将这种线性扩展到可能由非平衡态携带的弱场TRM。
Summary
By means of a phenomenological model of weak-field thermoremanent magnetization (TRM) it is possible to reproduce the complex behaviour of TRM and partial TRM (pTRM) to a good approximation. The model depicts a sample as a collection of statistically independent magnetization elements, each of which possesses a definite blocking and a definite unblocking temperature. Moreover, for weak fields, linear dependence of remanence on applied field is assumed for each magnetization element. These assumptions are sufficient to derive to first order the experimentally found relations between the different types of pTRMs. The kinematic equation, which is assumed to govern the cooling process in multidomain (MD) material, is obtained from the model when mean-field interaction is taken into account. The phenomenological model is supported by two physical approaches. Using magnetic phase theory the coefficients that occur in the kinematic equation as derived from the phenomenological model can be physically interpreted for an isotropic ensemble of uniaxial MD particles. A rigorous micromagnetic analysis of the thermal equilibrium state proves the linearity of equilibrium remanence as a function of a weak applied field. A statistical argument extends this linearity to weak-field TRM, which may be carried by non-equilibrium states.