Width Dependent Transport Properties of Manganite Nanostrips*

Manganites are known to have pronounced electronic phase separation (EPS) phenomena that dominate their physical properties. Under spatial confinement, the role of EPS may become different. In this work, we fabricate series of nanostrips with different widths from a single La_5/12Pr_5/24Ca_3/8MnO₃ thin film grown on LaAlO₃ (001) substrate. The widths of the nanostrips range from 1.5um to 50nm. We measured the transport properties of the nanostrips at different temperatures and external magnetic fields. Interestingly, the resistivity of the strips decreases with decreasing width. The phase competition was observed to occur most dramatically at 700 nm wide nanostrip, which has the highest critical magnetic fields for metal-insulator-transition. The interplay between EPS and the edge effect of the nanostrips plays a critical role for the observed width dependence of the transport behavior.