Incommensurate and commensurate magnetic structures of the ternary germanide CeNiGe₃

Abstract

The structural properties of CeNiGe3 have been investigated via electron diffraction and neutron powder diffraction (NPD). This ternary germanide crystallizes in the orthorhombic SmNiGe3-type structure (Cmmm space group). Electrical resistivity, ac- and dc-magnetization measurements show that CeNiGe3 orders antiferromagnetically below TN = 5.5(2) K and exclude the occurrence at low temperatures of a spin-glass state for CeNiGe3 as previously reported. Specific heat measurements and NPD both reveal two magnetic transitions, observed at TN1 = 5.9(2) K and TN2 = 5.0(2) K. Between TN1 and TN2, the Ce magnetic moments in CeNiGe3 are ordered in a collinear antiferromagnetic structure associated with the k1 = (100) wavevector and showing a relationship with the magnetic structure of the Ce3Ni2Ge7 ternary germanide. Below TN2, this k1 = (100) commensurate magnetic structure coexists with an incommensurate helicoîdal magnetic structure associated with k2 = (00.409(1)1/2). This last magnetic structure is highly preponderant below TN2 (93(5)% in volume). At 1.5 K, the Ce atoms in CeNiGe3 carry a reduced ordered magnetic moment (0.8(2) μB). This value, smaller than that obtained in Ce3Ni2Ge7, results from an important hybridization of the 4f(Ce) orbitals with those of the Ni and Ge ligands.

The electronic structure of CeNiGe3 and YNiGe3 superconductors by ab initio calculations

“…4. The imperfect nesting vector q in FS sheet I is in very good accord with the wave vector k=(0, 0.409, 1/2) of the helicoidal AFM order, observed experimentally [11]. [23] among Ce-Ni-Ge systems.…”

“…The competition between collinear and helicoidal, with the propagation vector k=(0, 0.409, 1/2), AFM ground states was reported for CeNiGe 3 [11]. In turn, the considered isostructural Y-based system has also been used as a non-magnetic counterpart to CeNiGe 3 [14,15].…”

Physical properties and anisotropies of the RNiGe3 series (R = Y, Ce–Nd, Sm, Gd–Lu)

“…For CeNiGe 3 the obtained m eff , y p , and T N from the polycrystalline average are consistent with the earlier polycrystalline sample studies [10,11]. PrNiGe 3 exhibits antiferromagnetic behavior with T N ¼18.7 K, which is the highest T N among light rare-earth compounds.…”

“…Polycrystalline samples of CeNiGe 3 and YNiGe 3 [10][11][12] and single crystalline samples of YbNiGe 3 [13,14], which are members of the RNiGe 3 family, have been synthesized and investigated over the past decade. Until now, however, practically no physical properties were reported for other rare-earth members of this series other than the crystal structure-type and lattice parameters [5].…”

Superconductivity and magnetism on flux-grown single crystals of NiBi3

“…A magnetic transition at this temperature involving the whole sample should give an overwhelming contribution to the specific heat. 34,39 Therefore, this anomaly is not due to a full bulk magnetic transition but rather to residual magnetism. No traces of this transition are found in other measurements.…”