Abstract
As a member of the Ruddlesden-Popper Ln(n+1)Ni(n)O(3n+1) series rare-earth-nickelates, Pr4Ni3O10 consists of infinite quasi-two-dimensional perovskite-like Ni-O based layers. Although a metal-to-metal phase transition at T-pt approximate to 157K has been revealed by previous studies, a comprehensive study of physical properties associated with this transition has not yet been performed. We have grown single crystals of Pr4Ni3O10 at high oxygen pressure, and report on the physical properties around that phase transition, such as heat-capacity, electrictransport, and magnetization. We observe a distinctly anisotropic behavior between in-plane and out-of-plane properties: a metal-to-metal transition at T-pt within the a-b plane, and a metal-to-insulator-like transition along the c axis with decreasing temperature. Moreover, an anisotropic and anomalous negative magnetoresistance is observed at T-pt that we attribute to a slight suppression of the first-order transition with magnetic field. The magnetic susceptibility can be well described by a Curie-Weiss law, with different Curie constants and Pauli-spin susceptibilities between the high-temperature and the low-temperature phases. The single crystal x-ray diffraction measurements show a shape variation of the different NiO6 octahedra from the high-temperature phase to the low-temperature phase. This subtle change of the environment of the Ni sites is likely responsible for the different physical properties at high and low temperatures.
Huangfu, Shangxiong