Layered transition metal pnictides investigated by experimental and computational methods
Doctor of Philosophy
Intensive research interest on transition metal pnictide compounds was stimulated by the discovery of unconventional superconductivity in Fe-pnictide compounds in 2008. A key observation in Fe-pnictide compunds is the intimate relationship between the structure, magnetism and superconductivity in those compunds. It is thus important to investigate a couple of transition metal pnictide compounds with similar structures to superconducting Fe-pnictide compounds, to elucidate how the magnetic and superconducting properties evolve with the type of crystallographic structure, lattice paramters and elements on a speci c site. In this thesis, R3T4As4O2 (R = La - Sm, T = Ni - Cu), which has a convolutional structure of 122 and 1111 Fe-pnictide superconductors, was investigated from the perspective of a couple of physical properties investigation as well as theoritical computation. The combination of experimental and theoretical methods reveals complex magnetic properties as the elements on rare earth and transition metal sites varies. Such observations would bene t a full understanding of the relationship between structure, magnetism and superconductivity in transition metal pnictide system as well the search for conventional superconductors with this speci c structure.
transition metal pnictides; magnetism; superconductivity