Spin disorder resistivity

The method proposed by Rao and Wallace (45) essentially takes into account (a) the Boltzmann distribution of rare earth ions among the crystal field states and (b) the contribution to the resistivity from inelastic scattering processes wherein the rare earth ion undergoes a transition from one crystal field state to another and the con- 

In the above expression N is the number of rare earth ions per unit volume, ms and m are the spins of the conduction electron states, i and i are the rare earth crystal field states, pj is the Boltzmann probability that the rare earth ion is in the crystal field state of energy Ej, and fa are given by 

It was shown that the above procedure gave a satisfactory description of the experimentally observed variation of spin disorder resistivity with temperature in CeAl2 

Evaluation of the spin-disorder resistivity in the second Bom approximation, when J Sf is negative shows an upturn at low temperatures (Kondo effect). Maranzana 

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The compound PrAl3 provides a classic example where results obtained from heat capacity, susceptibility and spin-disorder resistivity provide a unique description of... 

Influence of crystal field on spin-disorder resistivity The expression for the spin-disorder resistivity has the following form in the presence of a crystal field ... 

S" and S denote the diffusion thermopower of a non-magnetic RI compound and a magnetic RI compound, respectively. So, Sph, and Sspd are the contributions to the thermopower due to impurity scattering, phonon scattering, and spin-disorder scattering, respectively, p, po, Pph, and Pspd represent the total resistivity, and residual resistivity, the phonon resistivity, and the spin-disorder resistivity, respectively. 

The resistivity of GdgC , GdyNis, GdTCug, and GdgGa2 is shown in fig. 86. It can be seen that there are no important magnetic contributions to the resistivity. The spin-disorder resistivity does not disappear below and kinks or knee-like singularities are absent at T. Fig. 86, however, shows that the temperature... 

Temple and McEwen (1977) have evaluated the temperature dependence of Tr (PQ) for Pr, using the crystal field level scheme shown in fig. 6.17. In the absence of detailed information about the Fermi surface, po was determined by fitting the calculation to experimental data (after subtraction of the residual resistance) at 10 K, where the phonon contribution is much smaller than the magnetic contribution. As indicated by fig. 6.40, the spin-disorder resistivity has almost... 

Fig. 10. Total spin disorder resistivity, p versus (g-1/7(7+1) p, has been corrected by a small phonon contribution at (Stewart and Coles 1974).

The temperature and thickness dependence of the electric resistivity of Sm, Dy and Tm thin films (25-370 nm thick) was measured between 4.2 and 300 K by Dudas and Feher (1984, 1987), Dudas et al. (1985, 1986, 1987a-d, 1990), and Janos et al. (1987). For Dy films the Neel temperature and the residual resistivity ratio increase both as thickness increases. The thickness dependence of the spin-disorder resistivity is reported in fig. 6. In the case of Tm samples it is observed that the Neel temperature increases (from 49 to 54 K) and in-disorder resistivity decreases (from 35 to lOpQm) as thickness increases (fig. 7). Such results, and correlations with the crystalline orientations (basal plane of crystallites parallel or perpendicular to the substrate surface) correct the errors made by other investigators (see Gasgnier 1980). On the other hand the resistance ratio as a fimction of the temperature exhibits different kinds of curves as the thickness varies as measured for Tm films (fig. 8). Different magnetic transitions have been also observed. One can conclude that numerous kinds of anomalies were caused by hydrogen in solution in the metallic matric, in agreement with Dudas (1991), and also by structure... 

Fig. 6. Thickness dependence of the spin-disorder resistivity of thin Dy fihns. (By courtesy of Dr. J. Dud, Technical Univ., Kosice, Czechoslovakia).

A systematic study of the paramagnetic spin-disorder resistivity, Pm(T), has been carried out on the heavy RH2 compounds (R=Gd through Tm) by Burger et al. (1986a) and Daou... 

Spin-disorder resistivities, pS, measured at T=T, and ground-state magnetic moments, pos, for pure... 

O = crystal field operator equivalents Pspd = spin disorder resistivity ... 

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