Switching of the magnetic order inCeRhIn5−xSnxin the vicinity of its quantum critical point

Abstract

We report neutron diffraction experiments performed in the tetragonal antiferromagnetic heavy fermion system CeRhIn5−xSnx in its (x, T ) phase diagram up to the vicinity of the critical concentration xc ≈ 0.40, where long range magnetic order is suppressed. The propagation vector of the magnetic structure is found to be kIC=(1/2, 1/2, k l ) with k l increasing from k l =0.298 to k l =0.410 when x increases from x=0 to x=0.26. Surprisingly, for x=0.30, the order has changed drastically and a commensurate antiferromagnetism with kC=(1/2, 1/2, 0) is found. This concentration is located in the proximity of the quantum critical point where superconductivity is expected.

Determination of the magnetic structure of CePt2In7 by means of neutron diffraction

“…Remarkably, in these compounds, commensurate antiferromagnetism emerges in the vicinity of a quantum critical point where superconductivity also appears. Furthermore, in Sn-doped CeRhIn 5 , a drastic change in the magnetic order and a commensurate antiferromagnetism was observed in the proximity of the quantum critical point 15 where superconductivity is expected, but has not been observed so far. This suggests that a commensurate magnetic order might be favorable for the formation of superconductivity around a quantum critical point in this family of materials.…”

Magnetic structure of Cd-doped CeIrIn$_5$

“…However, we did not observe any additional magnetic Bragg peaks corresponding to an incommensurate magnetic wave vector. In particular, there are no peaks around Q = (1/2, 1/2, 0.3) characteristic of pure CeRhIn 5 at ambient pressure 24 or Q = (1/2, 1/2, 0.4) observed in either doped 10,12 or pressurized 13,15 CeRhIn 5 . An increased neutron intensity was observed at Q = (1/2, 1/2, 1).…”

“…To determine the Néel temperature, the data were fitted by a phenomenological function I/I 0 = 1 − (T /T N ) α , with α a free parameter. This function was successfully used to fit the temperature dependence of the magnetic Bragg peak intensity in other heavy fermion compounds, such as CePd 2 Si 2 25,26 , Sn-doped CeRhIn 5 12 , Cd-doped CeRhIn 5 18 , and CePt 2 In 7 27 . The best fit is obtained with α = 2.0 ± 0.5 and T N = 3.0 ± 0.1 K. The latter value is consistent with T N determined from previous specific heat 17 and resistivity 22 measurements.…”

Neutron scattering study of commensurate magnetic ordering in single crystal CeSb$_2$

“…It reveals an antiferromagnetic ground state below T N = 9.8 K without any further AFM-FM phase transition down to 2 K. The commensurate antiferromagnetic ordering of CeSb 2 can be described by the propagation vectors k = (−1, ±1/6, 0) and k = (±1/6, −1, 0). Moreover, as known that the Fermi surface topology might play an important role in the determination of the magnetic ordering [27], further DFT calculations as well as experimental technique are required to track the possible modification of Fermi surface.…”