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报道了两类典型元素替代的超导Y123相体系-YBa2(Cu1-xCox)3O7-δ(x=001,002)和YBa2(Cu1-yZny)3O7-δ(y=0005,0010)薄膜的电阻率温度特性(ρ(T))和Hall效应(RH(T)).研究表明,Co掺杂的Y123相体系十分类似于氧欠掺杂的情况,对Co掺杂的薄膜样品,由电阻率温度特性定义的赝能隙打开的温度T分别为193和225K.而Zn掺杂的样品没有观察到赝能隙打开对电阻率温度特性的影响.由Hall效应的测量和Hall角(cotθH)定义了另一个特征温度T0,
关键词:
赝能隙
Y123相
Hall效应 相似文献
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实验研究了高温超导体Hg09Tl02Ba2Ca2Cu3O8+δ的低温热导率与温度和磁场的关系,测量温度为7—20K,外加磁场为0—6T.结果表明,在不同外场下,超导体的热导率在实验温区内随温度的增加均单调增加;在固定的温度下外加磁场使超导体的热导率减小,并随外磁场的增加达到一个稳定值;热导的相对变化率κ(H)/κ(0)与磁场的关系以及热导率达到稳定值的磁场与测量温度有关.分析讨论了超导体中正常态电子在磁场下受磁通涡旋散射产生附加的热阻
关键词: 相似文献
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湖北省数学学会、武汉数学学会六届三次理事(扩大)会议于1990年4月20日至22日在华中理工大学举行.在本届58名理事中,有39名理事及一名顾问出席了会议.武汉市科协学会部李治湘部长、华中理工大学校长黄树槐教授光临了会议.此外,各大中专院校、中学以及地区教研室,有25名同志参加了本次会议. 相似文献
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The anisotropy of two successive transitions of the spin-ladder compound LiCu2O2 is studied by the specific heat ( C) under magnetic fields with H / / c and H / / ab (written as H^c and H^ab in the following) up to 14 T. The peak of specific heat at 24.5 K in zero field shifts to lower temperature when the field is increased and the magnitude of the peak is suppressed by the field. On the contrary, the peak of 22.5 K shifts to higher temperature, especially at 14 T. Its magnitude increases in the field of H^c, whereas it decreases in the field of H^ab. We calculate the entropy change between 21 K and 63 K. The different influence of the spin ordering by fields of different direction is obtained. Our experimental results suggest a mixed state between the long range incommensurate helimagnetic ground state and the higher-T short-range dimer liquid state. The temperature range of mixed state is shrunk with the increasing field. Possible mechanism is discussed. 相似文献
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Diffracted field distribution from a knife-edge truncated semi-Gaussian beam as an atomic (molecular) mirror
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We investigate the diffraction characteristics of an incident Gaussian
beam cut
by a straight edge bounding a semi-infinite opaque plane using Kirchhoff
scalar wave theory in the Fresnel limit, and propose a new and simple mirror
scheme to reflect atoms by using the intensity gradient induced by a
blue-detuned semi-Gaussian laser beam. The optical potential of the
diffracted light of the knife-cut semi-Gaussian beam for
$^{85}$Rb atom and its spontaneous emission probability are calculated and
compared with the performance of the evanescent-wave mirror. Our study shows
that the optical potential of the diffracted light of the semi-Gaussian beam
is far higher than that of the evanescent light wave, and the maximum normal
velocity of the incident atoms can be far greater than that of the
evanescent light wave under the same parameters, so the blue-detuned
semi-Gaussian beam, as a novel atomic mirror, can be used to efficiently
reflect cold atoms with a normal velocity of greater than 1 m/s. However,
the intensity gradient (force) of the diffracted light of the
semi-Gaussian-beam is much smaller than that of the evanescent light wave, so
its spontaneous emission probability is greater than that from the
evanescent-wave when the normal velocity of incident atoms is greater. 相似文献