ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We have investigated two antiferromagnetic superconductors, NdRh4B4 and SmRh4B4, which exhibit two quite different temperature dependencies of the upper critical field arising from two different mechanisms1 of the modification of superconductivity by the presence of antiferromagnetism. In order to further study these mechanisms, we have investigated the electromagnetic properties and have measured the penetration depths λ(T) of NdRh4B4 (Tc=5.45 K, TN1=1.31 K, and TN2=0.89 K) and SmRh4 B4 (Tc=2.2 K, TN=0.9 K), employing a tunnel diode oscillator at ∼30 MHz. Above the antiferromagnetic transition temperature (TN1 for NdRh4B4 and TN for SmRh4B4), the temperature dependencies of the penetration depths of these two superconductors fit the BCS theory well. We have found λ(0)=2170 and 980 A(ring) for NdRh4B4 and SmRh4B4, respectively. However, as temperature is lowered, λ(T) for NdRh4B4 increases near TN1 and then saturates near TN2, presumably owing to the molecular field effect.2 The spin-fluctuation effects,2 expected to be significant near TN2 for NdRh4B4 and TN for SmRh4B4, have not been observed within our experimental accuracy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.338784
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