Superconductivity, magnetism and valence fluctuations in rare earth-transition metal borides

Interpenetration of a 3D Icosahedral M@Ni12 (M=Al, Ga) Framework with Porphyrin‐Reminiscent Boron Layers in MNi9B8

“…Single crystalsw ere selected and the crystal structure wass olved and refined by using the same procedure as for AlNi 9 B 8 .D etails on the single-crystal data collection are listed in Table 1. The refined atomic coordinates and displacement parameters for GaNi 9 B 8 are listed in Ta bles 2and 3, respectively.Similarly,apossible deficit of the B3 atom at the 8f site was also found in GaNi 9 B 8 .T he occupation of the B3 atom at the 8f site could be refined to 0.7(1),t he isotropic displacement parameter B iso then reduced to 1.8 (7), and the residualss lightly reduced to R F = 0.056 and wR F 2 = 0.061, respectively. The interatomic distances and coordination numberso ft he atoms in AlNi 9 B 8 and GaNi 9 B 8 are collected in Ta ble S1 in the Supporting Information.…”

“…The crystal structure model obtained from the single-crystal XRD data is in excellent agreement with that derived from the powder XRD data. Final atomicc oordinates and anisotropic atomicd isplacement parameters are listed in Ta bles 2a nd 3, respectively.A dditionally,d ue to the larger displacementp arameter for the B3 atom at the 8f site compared with the other Ba toms, the occupation of the B3 atom was then refined, revealing that it might be partially occupied (with an occupation 0.70(4), ar educed displacementp arameter can be refined to 0.70(4)a nd 0.9(2), respectively,a nd in GaNi 9 B 8 ,t he occupation and B iso of B3 can be refined to 0.7(1) and 1.8 (7), respectively.…”

“…[1] In metalboridest his gives not only rise to the formation of one-,t wo-, or three-dimensional arrangements [2] of covalently bonded boron atoms, but also,d ue to complexs tructures,r esults in aw ealth of observed physical properties. They comprise, to mention only af ew of them, superconductivity, [3] collective magnetism, [4] Kondo lattice behavior, [5] heavy fermion behavior, [6] valencefluctuations, [7] andt hermoelectric properties. [8] Parallelb ut time-shifted to studies focusingo nt he boronbased frameworks tructures of bulk borides, the interesti n boron clusters, their shapes,a nd geometrical relationships arose.…”

Thermodynamic analysis of the quantum critical behavior of Ce-lattice compounds

“…No superconductive GS is expected in these alloyed systems because of the random distribution of the Ce neighbors. Nevertheless, the underlying superconductive possibilities cannot be excluded because in Ce(Rh 1Àx Ru x ) 3 B 2 the non-magnetic stoichiometric limit (x ¼ 1) shows low-temperature superconductivity [47].…”

TM7TM′6B8(TM= Ta, Nb;TM′ = Ru, Rh, Ir): New Compounds with [B6] Ring Polyanions

“…15,16 Depending on the metal-to-boron ratio, one-, two-and three-dimensional arrangements of covalently bonded boron atoms are formed. 12,14,17,18 The wealth of observed physical properties comprises collective magnetism, 19−22 superconductivity, 23−26 interplay of magnetism with superconductivity, 27 thermoelectricity, 28−30 valence fluctuations, 31 Kondo lattice behavior, 32 heavy fermion behavior, 33 etc. To mention only a few of the well-known materials of high technological relevance there are Nd 2 Fe 14 B-based permanent magnets, 34 boride-containing metallic glasses, 35 and LaB 6 -based electron emitters for electron microscopes.…”