Resistive Anomalies at Magnetic Critical Points
Resistive Anomalies at Magnetic Critical Points
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DOI：
10.1143/ptp.46.15
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发表时间：
1971-07
影响因子：
--
通讯作者：
S. Takada
中科院分区：
文献类型：
--
作者：
S. Takada
利用温度绿色函数和图解法，在传导电子与另一个电子系统（如d电子）通过自旋交换相互作用的模型中，计算了磁临界点附近自旋散射的电阻率。结果表明，铁磁临界点附近的电阻异常的起源不同于反铁磁转变点等其他临界点附近的电阻异常。在铁磁的情况下，电阻异常来自与短程自旋涨落相关的散射，因此电阻率dp/ dT的温度导数应该像磁比热一样变化，正如Fisher和Langer所建议的那样。另一方面，在具有周期性磁性结构的其他磁性情况下，例如稀土金属，电阻异常源于由于磁晶格矢量周围的长程自旋波动引起的临界散射。在这种情况下，dp_（dT）表示与-sign（t）（t_（1-<a+r-1））成比例的异常，如Suezaki和Mori所示，其中t=（T-Tc）/Tc，a和r分别是比热和磁化率的临界指数。高阶自旋波动的影响进行了检查，并示出是可以忽略不计的，只要在p的奇异性有关。
The electrical resistivity associated with spin scattering near magnetic critical points is calculated in the model where conduction electrons interact with another electron system such as d electrons through the spin exchange interaction using the temperature Green's functions and diagram technique. It is shown that the origin of the resistive anomaly near the ferromagnetic critical point is different from that near other critical points such as the antiferromagnetic transition point. In the ferromagnetic case the resistive anomaly arises from scattering associated with the short-range spin fluctuations and consequently the tem perature derivative of the resistivity dp/ dT should vary like the magnetic specific heat, as was suggested by Fisher and Langer. On the other hand, in other magnetic cases with periodic magnetic structures such as rare earth metals, resistive anomalies originate from critical scattering due to long-range spin fluctuations around the magnetic lattice vector. In such cases dpjdT shows the anomaly proportional to -sign(t) ltl-<a+r-1), as was shown by Suezaki and Mori, where t= (T-Tc)/Tc and a and r are the critical indices of the specific heat and the magnetic susceptibility respectively. Higher order effects of spin fluctuations are examined and shown to be negligible as far as singularities in p are concerned.