Magnetic properties ofGdT2Zn20(T=Fe, Co) investigated by x-ray diffraction and spectroscopy

Abstract

We investigate the magnetic and electronic properties of the GdT 2 Zn 20 (T = Fe and Co) compounds using X-ray resonant magnetic scattering (XRMS), X-ray absorption near-edge structure (XANES) and X-ray magnetic circular dichroism (XMCD) techniques. The XRMS measurements reveal that the GdCo 2 Zn 20 compound has a commensurate antiferromagnetic spin structure with a magnetic propagation vector τ = (2 ) below the Néel temperature (T N ∼ 5.7 K). Only the Gd ions carry a magnetic moment forming an antiferromagnetic structure with magnetic representation Γ 6 . For the ferromagnetic GdFe 2 Zn 20 compound, an extensive investigation was performed at low temperature and under magnetic field using XANES and XMCD techniques. A strong XMCD signal of about 12.5 % and 9.7 % is observed below the Curie temperature (T C ∼ 85 K) at the Gd-L 2 and L 3 edges, respectively. In addition, a small magnetic signal of about 0.06 % of the jump is recorded at the Zn K-edge suggesting that the Zn 4p states are spin polarized by the Gd 5d extended orbitals.

Tuning the electronic hybridization in the heavy fermion cage compound YbFe2Zn20with Cd doping

“…In contrast, the effective moment per formula unit remains almost unaltered around 5.0 µ B Conc. Liquid" for being close to the Stoner limit [11] and very recent spectroscopic studies have detected small but discernible moments induced on the cage structure, [23] which may be involved in the extra contribution to the effective moment. The obtained results are summarized in the Table 2.…”

“…It is notably larger than the Yb 3+ effective moment of 4.54 B µ and consistent with a previously reported larger value [10] of 4.7 B µ . Note that the reference compound YFe 2 Zn 20 has been labeled a 'nearly ferromagnetic Fermi liquid' for being close to the Stoner limit [11], and very recent spectroscopic studies have detected small but discernible moments induced on the cage structure [23], which may be involved in the extra contrib ution to the effective moment. The obtained results are summarized in the table 2.…”

“…At high temperatures the system behaves as a paramagnet with effective magnetic moment that comes mostly from the Yb 4f electrons, although the somewhat enhanced values in comparison to the Yb 3+ effective moment (see Table 2) points to additional magnetic contributions from the Fe and/or Zn atoms. [23] At low temperatures the screening of the magnetic moments by the ce causes a suppression of the magnetic response, leaving a Pauli-like enhanced magnetic susceptibility at χ(T = 0). For comparison, elemental Pd is a transition metal with d-electrons that are on the verge of magnetism, and features χ(T = 0) = 0.75 × 10 −3 emu/mol, [1] which is still two orders of magnitude smaller than the obtained values summarized in Table 2 for these heavy fermion compounds.…”

Magnetic structure of an antiferromagnet NdRh2Zn20 investigated by powder neutron diffraction

“…It is noteworthy that the propagation vector of k = (1/2, 1/2, 1/2) is common among those for the isostructural compounds RCo 2 Zn 20 (R = Gd and Tb) and PrIr 2 Zn 20 [14,15,16] for GdCo 2 Zn 20 is the same as that for NdRh 2 Zn 20 , where the alignment of the magnetic moments is described by the Γ 6 representation [14], while the magnetic structure of TbCo 2 Zn 20 is characterized by the Γ 5 representation.…”

“…This series of compounds display a variety of strongly correlated electronic phenomena such as multipole orders and superconductivity in PrTr 2 Zn 20 (Tr = Rh and Ir) and PrTr 2 Al 20 (Tr = V and Ti) [2,3,4,5,6,7], non-Fermi liquid behaviors in PrTr 2 Zn 20 (Tr = Rh and Ir) [8,9,10], and heavy fermion states in YbTr 2 Zn 20 (Tr = Fe, Ru, Os, Co, Rh, and Ir) [11,12,13]. Up till now, antiferromagnetic (AFM) structures of this series of compounds were only reported for RCo 2 Zn 20 (R = Gd and Tb) [14,15]. The antiferro-type quadrupole structure of PrIr 2 Zn 20 was determined by observing magnetic-field-induced magnetic dipoles [16].…”