MAGNETIC FIELD DEPENDENCE OF THE SUPERCONDUCTING ENERGY GAP
MAGNETIC FIELD DEPENDENCE OF THE SUPERCONDUCTING ENERGY GAP
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DOI：
10.1103/physrevlett.6.346
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发表时间：
1961-01-01
影响因子：
8.6
通讯作者：
DOUGLASS, DH
中科院分区：
文献类型：
--
作者：
DOUGLASS, DH
一阶产生消失的内部磁场。这与以下事实相一致：在这种情况下，旋转对应于50千高斯的平均场，而在相同（室温）温度下，Sm和Dy的旋转是兆高斯量级。如果我们试图通过考虑更高的多重态来解释这种小的resid-n = l旋转，我们会发现很难解释所观察到的旋转的符号。特别地，如果我们假设Eu中的J= 1的低位态（它对Eu离子的磁矩有贡献）是超精细相互作用的原因，那么就预言了负转动，这与实验不符。很明显，在Sm”和Dy '中，与Fe中的情况不同，s电子与f壳层电子交换耦合对内部磁场的贡献不足以改变所观察到的内部磁场的符号。然而，在Eu或Gd的情况下，场的主要来源可能是交换耦合贡献。如果交换耦合的贡献没有明显不同的各种稀土，这种解释是一致的Sm和Dy中获得的结果。进一步假设交换耦合相互作用为A ′ I ~ 5形式，则Eu或Gd的A ′符号为负。
that to first order produce vanishing internal magnetic fields. This is in agreement with the fact that the rotations in this case correspond to average fields of 50 kilogauss, while it is of the order of megagauss in Sm and Dy at the same (room) temperature. If one tries to account for this small resid~"= l rotation by taking intoaccount higher multiplets, one finds it difficult to ex-plain the observed sign of the rotation. In particular, if one assumes thatthe low-lying J= 1 state in Eu (which contributes to the magnetic moment of the Eu ion) is responsible for the hy-perfine interaction, a negative rotation is pre-dicted, in disagreement with experiment. It is clear that in Sm" and Dy', unlike the case in Fe, the contributions to the internal magnetic field arising from s electrons exchangecoupled to the f-shell electrons are not sufficiently large to change the sign of the observed internal field. In the case of Eu or Gd, however, the main source of field may be the exchangecoupled contribution. If the exchange-coupled contribution does not vary appreciably among the various rare earths, this interpretation is consistent with the results obtained in Sm and Dy. With thefurther assumption that the ex-change-coupled interaction is of the form A'I~ 5, the sign of A'for Eu or Gd is determined to be negative.