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文中报道非晶Cu_(33)Y_(67)低温电阻和磁阻的测量结果。这种合金是在He气氛中以熔化-自旋技术制备的。相互作用效果可以为4.5K以下的低温电阻提供一个-T~(1/2)形式的贡献。在稍高的温度,其变化规律也可以通过相互作用和弱定域化的联合来解释。上至1.8T的磁阻测量揭示出一个具有自旋-轨道散射较强影响的弱定域化效果。Cu_(33)Y_(67)的磁阻测量值比弱定域化预言的大。如果把弱定域化的理论预言强度增大3倍,则可以在整个测量磁场范围内与实验值拟合。自旋-轨道散射时间τ_(50)和非弹性散射时间τ_i作为两个拟合参量。τ_(50)不随温度变化,而从对电阻和磁阻分别拟合所确定的τ_i与温度关系是互相符合的。 相似文献
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文中介绍了非晶Cu_(72)Y_(78)在温区1.5—30K的电阻和磁阻测量结果,应用磁场高达17kOe。由测量结果可确定弱定域化对电阻温度关系的贡献。如果计及由于相互作用引起的-2~(1/T)项,则高达20K的电阻-温度关系可以很好地被描述。电阻最小值正是由弱定域化和相互作用共同作用的结果。 相似文献
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文中报道非晶Cu33Y67低温电阻和磁阻的测量结果。这种合金是在He气氛中以熔化-自旋技术制备的。相互作用效果可以为4.5K以下的低温电阻提供一个-T1/2形式的贡献。在稍高的温度,其变化规律也可以通过相互作用和弱定域化的联合来解释。上至1.8T的磁阻测量揭示出一个具有自旋-轨道散射较强影响的弱定域化效果。Cu33Y67的磁阻测量值比弱定域化预言的大。如果把弱定域化的理论预言强度增大3倍,则可以在
关键词: 相似文献
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A series of microstructures designed to pin domain walls (DWs) in (Ga,Mn)As with perpendicular magnetic anisotropy has been employed to determine extrinsic and intrinsic contributions to DW resistance. The former is explained quantitatively as resulting from a polarity change in the Hall electric field at DW. The latter is 1 order of magnitude greater than a term brought about by anisotropic magnetoresistance and is shown to be consistent with disorder-induced mistracking of the carrier spins subject to spatially varying magnetization. 相似文献
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一种新的钙钛矿结构的庞磁电阻氧化物La0.9Sb0.1MnO3已用固态反应方法制 成,通过超导量子干涉器件(SQUID)装置测量研究了它的电输运性质和磁性质.x射线光电子 能谱分析证明,该氧化物中Sb的价态是+5价,因此该氧化物是一种新的电子掺杂型庞磁电阻 材料.
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钙钛矿结构
0.9Sb0.1MnO3')" href="#">La0.9Sb0.1MnO3
电子掺杂
庞磁电阻 相似文献
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Y. Wang N.F. Chen X.W. Zhang X.F. Chen X.L. Yang Z.G. Yin Y.M. Bai 《Physics letters. A》2009,373(22):1983-1987
The electric-tunable spin-independent magnetoresistance effect has been theoretically investigated in ballistic regime within a two-dimensional electron gas modulated by magnetic-electric barrier nanostructure. By including the omitted stray field in previous investigations on analogous structures, it is demonstrated based on this improved approximation that the magnetoresistance ratio for the considered structure can be efficiently enhanced by a proper electric barrier up to the maximum value depending on the specific magnetic suppression. Besides, it is also shown the introduction of positive electrostatic modulation can effectively overcome the degradation of magnetoresistance ratio for asymmetric configuration and enhance the visibility of periodic pattern induced by the size effect, while for an opposite modulation the system magnetoresistance ratio concerned may change its sign. 相似文献
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S. Senoussi 《Solid State Communications》1983,45(5):407-410
The low field longitudinal magnetoresistance, Δp/po, of Au + 14.5%at.Fe is measured as a function of field (- 1kG < H < 1kG), temperature (1.2K, 140K) and annealing conditions. When the sample is annealed and quenched from 950 C, the low field (~ 100 G) Δp/po versus H curve exhibits two sharp peaks at about 35 and 75 K respectively. The low temperature peak is associated with a spin glass transition (Tg) whereas the high temperature one would correspond to a ferromagnetic transition (Tc). The spin-glass state such as T ? Tg is characterised by a clear quadratic behavior of Δp/po as a function of H whereas in the ferromagnetic state (Tg < T < Tc), the magnetoresistance is completely dominated by a linear term. Quenching the sample from 550C considerably reduces the overall magnetoresistance, suppresses the linear term and transforms the double peak structure into a a single rather broad cusp of a spin-glass type. To help interpreting the above results, we also carried out low field magnetoresistance measurements on Pd + 0.2 at.%Fe, Pd + 2 at.%Mn and Pd + 10 at.%Mn at low temperatures. 相似文献
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A. B. Granovsky M. Ilyn A. Zhukov V. Zhukova J. Gonzalez 《Physics of the Solid State》2011,53(2):320-322
The anomalous behavior of magnetoresistance has been revealed in a number of granular microwires. In contrast to the giant
magnetoresistance of granular alloys, which is associated with the spin-dependent scattering in the bulk of grains and at
their surface, is linear in the square of the magnetization, and decreases with an increase in temperature, the magnetoresistance,
for example, in Co10Cu90 microwires is negative, increases with an increase in temperature below the Curie temperature, and does not reach saturation
in the field dependence in the high-field range. A simple mechanism of negative giant magnetoresistance due to scattering
of spin-polarized charge carriers by impurity magnetic moments localized in the nonmagnetic intergranular spacers has been
proposed taking into account that a considerable part of magnetic ions in microwires exhibiting this behavior is dissolved
in the intergranular spacers. It has been shown that the corresponding contribution to magnetoresistance can reach 10–20%. 相似文献
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The theoretically predicted and long-sought intrinsic saturation of the transverse magnetoresistance of the alkali metals
has finally been observed after sufficiently reducing the masking effect of the large superimposed linear magnetoresistance
which is attributed to such classical considerations as geometry, Hall angle and non-uniform current distribution. The observed
saturation values were about 100 times smaller than those observed previously in complicated metals but were still much too
large to be explained only by Fermi surface anisotropy. The saturation phenomena contradict Kohler's rule but can be plausibly
explained by mean free path anisotropy due predominantly to electron-phonon scattering mechanisms. 相似文献
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The magnetoresistance of dilute AuCr alloys (2.3–322 at.ppm) has been measured in a wide region of temperature (5-3K) and of magnetic field (up to 60 kG).The “modified Kohler's rule” was used to extract the spin dependent magnetoresistance (?M) from measured total magnetoresistance.The results has shown that, except for the most dilute specimen, ?M includes explicitly a positive component in addition to the ordinary negative magnetoresistance proportional to log (H/T). We have attributed this positive ?M to the effect of the interactions between the Cr impurities by taking consideration of the generalized phase shift expression of magnetoresistance proposed by Soultie. 相似文献
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The magnetoresistance in the system of quantum dots with hopping conduction and filling factor 2 < ν < 3 in the limit of small quantum dots has been considered. In this case, hopping conduction is determined by p states. It has been shown that the system exhibits negative magnetoresistance associated with a change in the wavefunctions of p states in a magnetic field. This mechanism of magnetoresistance is linear in magnetic field in a certain range of fields and can compete with the known interference mechanism of magnetoresistance. The magnitude of this magnetoresistance is independent of the temperature at fairly low temperatures and increases with a decrease in the size of a quantum dot. 相似文献