Structural transformation in inverse-perovskite RE Pt 3 B (RE = Sm, Gd-Tm) associated with large volume reduction

In this work, we report structural phase transformation of tetragonal inverse-perovskite REPt 3 B (RE = Sm, Gd-Tm) compounds to cubic perovskite structure, with large volume reduction of about 9% (reduction of c-axis ∼ 17%, increase in a-axis ∼ 5%). The structural stability of the cubic phase however, could only be maintained by lowering the lattice parameter of the o(cid:27)-stoichiometric REPt 3 B x ( x < 1), formed in the process of annealing. The combined e(cid:27)ect of phase transformation and stoichiometric defect are argued to be responsible for the observed volume collapse. Unexpectedly, the application of large hydrostatic pressure of ∼ 20 GPa, does not have any signi(cid:28)cant e(cid:27)ect on the crystal structure. Neutron di(cid:27)raction studies and heat capacity measurements unambiguously con(cid:28)rm di(cid:27)erent magnetic transition temperatures in the tetragonal and cubic phases. The di(cid:27)erent physical properties of these two phases demonstrate the interrelation between crystal chemistry and the physics of the system. The syn-thetic route to cubic REPt 3 B x identi(cid:28)ed in this work may be utilized to prepare new ternary rare-earth intermetallics in a cubic perovksite form which was previously found to facilitate unconventional superconductivity.

[1]  M. Schlipf,et al.  Melting of Pb Charge Glass and Simultaneous Pb-Cr Charge Transfer in PbCrO3 as the Origin of Volume Collapse. , 2015, Journal of the American Chemical Society.

[2]  吴敏,et al.  Pressure-Induced Valence Change and Semiconductor-Metal Transition in PbCrO3 , 2014 .

[3]  J. Zhu.  Pressured-Induced Reversal between Thermal Contraction and Expansion in Ferroelectric PbTiO$_3$ , 2013 .

[4]  Masaki Azuma,et al.  Pressure-induced spin-state transition in BiCoO3. , 2010, Journal of the American Chemical Society.

[5]  A. Pandey,et al.  Magnetism in ordered metallic perovskite compound GdPd3BxC1-x , 2009 .

[6]  P. Fischer,et al.  Determination of frustrated and non-frustrated magnetic structures of hexagonal and orthorhombic TbPdAl , 2009 .

[7]  E. Haller,et al.  Multiband Superconductivity in Heavy Fermion Compound CePt3Si without Inversion Symmetry: An NMR Study on a High-Quality Single Crystal , 2008, 0811.2043.

[8]  I. Nekrasov,et al.  Ab initio exchange interactions and magnetic properties of the Gd 2 Fe 17 iron sublattice: Rhombohedral versus hexagonal phases , 2008, 0809.3905.

[9]  M. Azuma,et al.  Magnetic ground-state of perovskite PbVO3 with large tetragonal distortion. , 2008, Inorganic chemistry.

[10]  Katsuhiro Maeda,et al.  Specific Heat Study of Magnetic and Superconducting Transitions in CePt3Si , 2008, 0802.2759.

[11]  C. Loison,et al.  Electronic structures of intermetallic borides RPd3Bx (R=rare-earth metals) , 2007 .

[12]  M. Salamon,et al.  Spurious second transition in the heavy-fermion superconductor CePt3Si , 2005 .

[13]  K. Knight,et al.  A reduced moment antiferromagnetic Kondo lattice compound: Ce8Pd24Ga , 2004 .

[14]  E. Bauer,et al.  Heavy fermion superconductivity and magnetic order in noncentrosymmetric CePt3Si. , 2003, Physical review letters.

[15]  R. Naik,et al.  High-pressure Raman studies of polycrystalline BaTiO 3 , 1998 .

[16]  R. Hoffmann,et al.  The TiNiSi Family of Compounds: Structure and Bonding , 1998 .

[17]  C. Zheng.  Bonding and Dynamics of the ThCr2Si2 and CaBe2Ge2 Type Main Group Solids: A Monte Carlo Simulation Study. , 1993 .

[18]  M. Sergent,et al.  Polymorphism and physical properties of LnNi2As2 compounds (Ln = La → Gd) , 1988 .

[19]  H. Takei,et al.  Studies on the perovskite solid solution Er(Rh, M)3By (M ≡ Pd, Pt and 0 ⩽ y ⩽ 1) , 1987 .

[20]  C. Zheng,et al.  Donor-acceptor layer formation and lattice site preference in the solid: the CaBe2Ge2 structure , 1986 .

[21]  C. Zheng,et al.  Making and breaking bonds in the solid state: the ThCr2Si2 structure , 1985 .

[22]  I. R. Harris,et al.  The constitution and structure of some rare earth-platinum alloys in the range 20–35% rare earth , 1973 .

[23]  A. P. Hammersley,et al.  Two-dimensional detector software: From real detector to idealised image or two-theta scan , 1996 .