Phase equilibrium diagram of the Hf-Fe-Sn system at 1070 K

Experimental studies of the phase equilibrium diagram of the Hf-Fe-Sn ternary system at 1070 K were performed by X-ray powder diffractometry, scanning electron microscopy and electron probe microanalysis techniques in the whole concentration range. At annealing temperature four ternary compounds are realized: Hf6FeSn2 (K2UF6 structure type, space group P-62m), Hf1.8Fe5Sn3.8 (Hf1.82Fe5Sn3.82 structure type, space group Cmmm), Hf3Fe4Sn4 (Zr3Fe4Sn4 structure type, space group Pnma), and Hf9Fe3.7Sn10.3 (Hf9Fe4Sn10 structure type, space group Cmc21). An existence of the Hf1-xFe2+x-ySny solid solution formed by substitution of the iron atoms by tin in the Hf1-xFe2+x (MgZn2-type) binary compound up to 19 at. % Sn was found. Solubility of Fe in the Hf5Sn3 binary (Mn5Si3-type) extends up to 10 at. % (a=0.8363(2)-0.8324(4), c=0.5726(1)-0.5686(4) nm).

Weighted composition operators from Bloch-type into Bers-type spaces

In this paper we consider the weighted composition operator uC_{\varphi} from Bloch-type space B^{\alpha} into Bers-type space H_{\beta}^{\infty}, in three cases, \alpha>1, \alpha=1 and \alpha<1. We give the necessary and sufficient conditions for boundedness and compactness of the above operator.

EuTMg2 (T = Pd, Ag, Ir, Pt, Au), EuTCd2 (T = Pd, Pt, Au) and CaRhMg2 – intermetallic compounds with orthorhombically distorted tetrahedral magnesium (cadmium) substructures

The magnesium- and cadmium-rich intermetallic phases EuTMg2 (T = Rh, Pd, Ag, Ir, Pt, Au), EuTCd2 (T = Pd, Pt, Au) and CaRhMg2 were synthesized from the elements in sealed niobium or tantalum ampoules and with heat treatments in muffle or induction furnaces. The samples were characterized by powder X-ray diffraction and the structures were refined from single crystal X-ray diffractometer data. EuTMg2 (T = Pd, Ag, Pt, Au) and EuTCd2 (T = Pd, Pt, Au) crystallize with the MgCuAl2 type, space group Cmcm, while EuRhMg2, EuIrMg2 and CaRhMg2 adopt the YSiPd2 type, space group Pnma. The striking crystal chemical motif of both series of compounds are networks of puckered Mg(Cd) hexagons in ABAB stacking sequence that derive from the aristotype AlB2; however, with different tiling. Temperature dependent magnetic susceptibility and 151Eu Mössbauer spectroscopic measurements indicate stable divalent europium. Antiferromagnetic ordering sets in at 20.2 (EuIrMg2), 22.3 (EuPdMg2), 21.3 (EuAgMg2), 10.9 (EuPdCd2) and 15.5 K (EuPtCd2), respectively. The stable antiferromagnetic ground states are substantiated by metamagnetic transitions. The 151Eu isomer shifts show a linear correlation with the valence electron count for the whole series of EuTMg2, EuTCd2, EuTIn2 and EuTSn2 phases.