Jeffrey B. Whalen

Area of research

Electronic, Optical and Magnetic Materials · Condensed Matter Physics

Research interest

Research topics from publications: Single crystal synthesis and magnetism of the BaLn2O4 family (Ln = lanthanide); Ba 3 CrN 3 H: A New Nitride-Hydride with Trigonal Planar Cr 4+; Flux Growth and Magnetoresistance Behavior of Rare Earth Zintl Phase EuMgSn; Evidence for an internal-field-induced spin-flop configuration in the extended kagome YBaCo4O7; Synthesis and Crystal Structure of the Layered Lanthanide Oxychlorides Ba3Ln2O5Cl2; Ba2TeO: A new layered oxytelluride; Growth of EuO single crystals at reduced temperatures; Locating anionic hydrogen in Ba3(Yb,Lu)2O5H2: A combined approach of X-ray diffraction, crystal chemistry, and DFT calculations; ChemInform Abstract: Competing Phases, Complex Structure, and Complementary Diffraction Studies of R3‐δFeAl4‐xMgxTt2 Intermetallics (R: Y, Dy, Er, Yb; Tt: Si or Ge; x < 0.5); ChemInform Abstract: Flux Growth and Magnetoresistance Behavior of Rare Earth Zintl Phase EuMgSn. Representative work: The nitride-hydride Ba3CrN3H was obtained in single crystalline form using flux growth techniques based on alkaline earth metals. Ba3CrN3H crystallizes in the hexagonal space group P63/m (Nr 176), with the lattice parameters a = 8.0270(2) Å, c = 5.6240(1) Å, and Z = 2. The structure comprises [CrN3]5– trigonal planar units and [HBa6]11+ octahedral units. The presence of anionic hydrogen in the structure has been verified by 1H NMR experiments. DFT calculations show that the addition of hydrogen increases the stability of the phase versus Ba3CrN3. The two d-electrons of Cr4+ are located in the nonbonding dz2 orbital, rendering Ba3CrN3H nonmagnetic and insulating Reactions of europium and tin in 1:1 Mg/Al mixed flux produce large crystals of EuMgSn. This phase crystallizes with the TiNiSi structure type in orthorhombic space group Pnma (a = 8.0849(7) Å, b = 4.8517(4) Å, c = 8.7504(8) Å, Z = 4, R1 = 0.0137). The crystal structure features europium cations positioned between puckered hexagonal layers comprised of magnesium and tin atoms. Magnetic susceptibility measurements indicate the europium in this phase is divalent, which suggests that the compound is possibly valence-balanced as Eu(2+)Mg(2+)Sn(4-). However, EuMgSn is a metal as indicated by density of states calculations and electrical resistivity behavior. This phase exhibits antiferromagnetic