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تسجيل مستخدم جديدMagnetic-field enhanced aniferromagnetism in non-centrosymmetric heavy-fermion superconductor CePt$_3$Si
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The effect of magnetic field on the static and dynamic spin correlations in the non-centrosymmetric heavy-fermion superconductor CePt$_3$Si was investigated by neutron scattering. The application of a magnetic field B increases the antiferromagnetic (AFM) peak intensity. This increase depends strongly on the field direction: for B${parallel}$[0 0 1] the intensity increases by a factor of 4.6 at a field of 6.6 T, which corresponds to more than a doubling of the AFM moment, while the moment increases by only 10 % for B${parallel}$[1 0 0] at 5 T. This is in strong contrast to the inelastic response near the antiferromagnetic ordering vector, where no marked field variations are observed for B${parallel}$[0 0 1] up to 3.8 T. The results reveal that the AFM state in CePt$_3$Si, which coexists with superconductivity, is distinctly different from other unconventional superconductors.
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$rm CePt_3Si$ is a novel heavy fermion superconductor, crystallising in the $rm CePt_3B$ structure as a tetragonally distorted low symmetry variant of the $rm AuCu_3$ structure type. $rm CePt_3Si$ exhibits antiferromagnetic order at $T_N approx 2.2$
K and enters into a heavy fermion superconducting state at $T_c approx 0.75$ K. Large values of $H_{c2} approx -8.5$ T/K and $H_{c2}(0) approx 5$ T refer to heavy quasiparticles forming Cooper pairs. Hitherto, $rm CePt_3Si$ is the first heavy fermion superconductor without a center of symmetry.
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