McCandless, Gregory | Search NASA

DOE OSTI2020

Peroxide-Templated Assembly of a Trimetal Neodymium Complex Single-Molecule Magnet

In this study, we present a tri-metal neodymium complex with two notable qualities. Firstly, the assembly of the complex is templated by peroxide derived from atmospheric oxygen. Secondly, the bulk material behaves as a super-paramagnet, implying that the individual complexes are molecular magnets. The peroxide-templated assembly is possible due to the confluence of the high oxophilicity of neodymium along with the use of an azeotropic distillation synthesis method, which excludes water but admits oxygen. SQUID magnetometer measurements show an extremely high magnetic susceptibility as well as a lack of remanence.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2011

Structure-property coupling in Sr3(Ru1 xMnx)2O7

Layered ruthenates are prototype materials for the study of structure-property correlations. We report the structural and physical properties of double-layered perovskite Sr3(Ru1 xMnx )2O7 single crystals with 0 < x < 0.7. Single-crystal x-ray diffraction refinements reveal that Mn doping on the Ru site leads to the shrinkage of unit-cell volume and the disappearance of (Ru/Mn)O6 octahedron rotation when x > 0.16, but the crystal structure remains tetragonal. Upon doping, the electrical resistivity reveals a metallic character (d /dT > 0) at high temperatures but insulating behavior (d /dT < 0) below a characteristic temperature TMIT. Interestingly, TMIT is different from TM, at which magnetic susceptibility reaches maximum. While TMIT increases monotonically with increasing x,TM displays a nonmonotonic dependence with x even though the effective spin increases from S 1 (x = 0) to 3/2 (x = 0.7). The phase diagram consists of three distinct magnetic ground states due to local structure change.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗