Magnetic structure and critical behavior ofGdRhIn5: Resonant x-ray diffraction and renormalization group analysis

Abstract

The magnetic structure and fluctuations of tetragonal GdRhIn 5 were studied by resonant x-ray diffraction at the Gd L II and L III edges, followed by a renormalization group analysis for this and other related Gd-based compounds, namely Gd 2 IrIn 8 and GdIn 3 . These compounds are spin-only analogs of the isostructural Ce-based heavy-fermion superconductors. The ground state of GdRhIn 5 shows a commensurate antiferromagnetic spin structure with propagation vector τ = (0, antiferromagnetic (AFM) interactions. While a large J 1 /J 2 ratio favors an antiparallel alignment along the three directions (the so-called G-AFM structure), a smaller ratio favors the magnetic structure of GdRhIn 5 (C-AFM). In particular, it is inferred that the heavy-fermion superconductor CeRhIn 5 is in a frontier between these two ground states, which may explain its non-collinear spiral magnetic structure. The critical behavior of GdRhIn 5 close to the paramagnetic transition at T N = 39 K was also studied in detail. A typical second-order transition with the ordered magnetization critical parameter β = 0.35 was experimentally found, and theoretically investigated by means of a renormalization group analysis. Although the Gd 4f 7 electrons define a half-filled, spherically symmetrical shell, leading to a nearly isotropic spin system, it is argued that a significant spin anisotropy must be claimed to understand the second order of the paramagnetic transition of GdRhIn 5 and the related compound Gd 2 IrIn 8 .

La-dilution effects in antiferromagneticTbRhIn5single crystals

“…Further, this result may be indicative that the balance between the Tb first-and second-neighbor interactions ͑J 1 and J 2 , respectively͒ is the same as for the nondoped TbRhIn 5 compound. 24,26 Nonetheless, from our recent data we cannot determine the direction of magnetic moments in the Tb sublattice through the comparison between observed and calculated integrated intensities of magnetic peaks because only three reflections from the same AFM domains were reached with our experimental setup. Therefore, new data in the resonant condition are required to know the moment orientation for this La-doped sample.…”

“…In this sense, the study of structurally related compounds within the R m M n In 3m+2n family has been successfully used to understand the evolution of 4f-electron magnetism for many members of the series in situations where some of the contributions above can be negligible. [21][22][23][24][25][26][27][28] For instance, in the Gd m M n In 3m+2n ͑M = Rh and Ir͒ compounds, as Gd 3+ is a pure ͑S =7/ 2,L =0͒ spin ion, the RKKY interaction and its dependence with electronic structure is the main contribution. [22][23][24] For the Nd-and Tb-based members of the R m M n In 3m+2n family, 21,25,26,28,29 both RKKY interaction and CEF effects are present, and the CEF contribution can be evaluated for Krammers ͑Nd 3+ , J =9/ 2͒ and non-Krammers ions ͑Tb 3+ , J =6͒ without the complexity of the Kondo lattice behavior of the Ce-based compounds.…”

Why the Co-based 115 compounds are different: The case study ofGdMIn5(M=Co,Rh,IrFacio1, Betancourth2, Pedrazzini3 et al. 2015Phys. Rev. B150140View full textAdd to dashboardCite

“…The lowest energy configuration for the three Gd compounds is antiferromagnetic (AF3) which corresponds to the measured structure in GdRhIn 5 via resonant x-ray diffraction experiments, NdRhIn 5 in neutron diffraction experiments and the inferred structure of DyRhIn 5 and HoRhIn 5 in magnetization experiments. [28][29][30] This magnetic configuration is associated with the competition of the first-neighbour K 0 and the second neighbour K 1 antiferromagnetic exchange couplings that lead to ferromagnetic chains in the GdIn 3 plane and an antiferromagnetic interplane coupling K 2 that leads to an antiferromagnetic configuration between GdIn 3 planes. [28][29][30] The total energy for each magnetic configuration is presented in Table II.…”

“…[28][29][30] This magnetic configuration is associated with the competition of the first-neighbour K 0 and the second neighbour K 1 antiferromagnetic exchange couplings that lead to ferromagnetic chains in the GdIn 3 plane and an antiferromagnetic interplane coupling K 2 that leads to an antiferromagnetic configuration between GdIn 3 planes. [28][29][30] The total energy for each magnetic configuration is presented in Table II.…”

Kramers degeneracy in a magnetic field and Zeeman spin-orbit coupling in antiferromagnetic conductors

“…Gadolinium antiferromagnets (see [79,80], and Table I in [81]) offer two important advantages for an experimental study of the Zeeman spin-orbit coupling. Firstly, their often elevated Néel temperature T N (such as 134 K for GdAg, or 150 K for GdCu) facilitates experimental access to temperatures well below T N , where thermal fluctuations of antiferromagnetic order are frozen out.…”