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11.
Das P White JS Holmes AT Gerber S Forgan EM Bianchi AD Kenzelmann M Zolliker M Gavilano JL Bauer ED Sarrao JL Petrovic C Eskildsen MR 《Physical review letters》2012,108(8):087002
We present small angle neutron scattering studies of the vortex lattice (VL) in CeCoIn5 with magnetic fields applied parallel (H) to the antinodal [100] and nodal [110] directions. For H is parallel to [100], a single VL orientation is observed, while a 90° reorientation transition is found for H is parallel to [110]. For both field orientations and VL configurations we find a distorted hexagonal VL with an anisotropy, Γ=2.0±0.05. The VL form factor shows strong Pauli paramagnetic effects similar to what have previously been reported for H is parallel to [001]. At high fields, above which the upper critical field (H(c2)) becomes a first-order transition, an increased disordering of the VL is observed. 相似文献
12.
Biswas PK Lees MR Balakrishnan G Liao DQ Keeble DS Gavilano JL Egetenmeyer N Dewhurst CD Paul DM 《Physical review letters》2012,108(7):077001
The flux-line lattice in CaAlSi has been studied by small-angle neutron scattering. A well-defined hexagonal flux-line lattice is seen just above H(c1) in an applied field of only 54 Oe. A 30° reorientation of this vortex lattice has been observed in a very low field of 200 Oe. This reorientation transition appears to be first-order and could be explained by nonlocal effects. The magnetic field dependence of the form factor is well-described by a single penetration depth of λ=1496(1) ? and a single coherence length of ξ=307(1) ? at 2 K. At 1.5 K, the penetration depth anisotropy is γ(λ)=2.7(1), with the field applied perpendicular to the c axis, and agrees with the coherence length anisotropy determined from critical field measurements. 相似文献
13.
P. Vonlanthen J.L. Gavilano B. Ambrosini D. Heisenberg F. Hulliger H.R. Ott 《Zeitschrift für Physik B Condensed Matter》1997,102(3):347-357
We report on In nuclear magnetic resonance (NMR) and nuclear quadrupolar resonance (NQR) measurements on the new heavy-electron compound CePdZIn over a wide temperature range, from 45 mK up to 30 K. CePd2In undergoes an antiferromagnetic (AF) phase transition at T N = 1.23 K involving small localised Ce moments of 0.11 μB. In zero field, the spin-lattice relaxation rate T 1 ?1 (T) shows remarkable changes in its temperature dependence. Above 3 K, T 1 ?1 is constant and 850 sec?1. Between T N and 2T N, (T 1 T)?1 = 330 (Ksec)?1, but rapidly decreases below T N. A Korringatype relaxation, characteristic for simple metals at low temperatures, with (T 2 T)?1 = 17(Ksec)1 is resumed below 0.6 K. This value is an order of magnitude larger than (T 1 T)?1 for LaPd2In and therefore is associated with low-energy excitations of the itinerant charge carriers with 4f symmetry. The T 1 ?1 data at various non-zero magnetic fields fall on a single curve when plotted as a function of (T/H) if H exceeds 3.5 T. Thus the AF ordering, the 4f moment fluctuations and the Kondo screening are drastically suppressed by the application of fields H of the order of 3.5 T. 相似文献
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15.
Thermodynamic calculations, developed here, show that a considerable fraction of the observed low-temperature nuclear spin-lattice
relaxation rate and specific heat of CeAl2-both varying linearly with temperature-may be due to the existence of new low-frequency features in the spin-excitation spectrum
of incommensurate magnetic structures. 相似文献
16.
We present the results of nuclear magnetic resonance (NMR) studies down to very low temperatures for two U compounds, UCu3.5Pd1.5 and U0.8Y0.2Pd3, where the conduction electrons experience strong interactions and for which the temperature dependences of the thermal and transport properties do not obey the expectations of a simple Fermi-liquid model. Also the temperature and field dependences of the nuclear magnetization recovery of UCu3.5Pd1.5 in Cu nuclear quadrupole resonance show unusual features that cannot be reconciled with common expectations for a simple metal, but they are well accounted for by the Kondo disorder model. For U0.8Y0.2Pd3, our Y NMR results indicate a distribution of internal static magnetic fields at the Y sites and a small temperature-dependent enhancement of the spin-lattice relaxation rateT 1 ? with respect to YPd3. The NMR spectra are consistent with the presence of very small frozen U moments, but the temperature dependence of the spin-lattice relaxation rate indicates a more complicated situation. 相似文献