Relations between structural distortions and transportproperties in Nd0.5Ca0.5MnO3 strained thinfilms

Abstract

Strained thin films of charge/orbital-ordered (CO/OO) Nd0.5Ca0.5MnO3 with various thicknesses havebeen grown on (100) SrTiO3 and (100) LaAlO3 substrates, byusing the pulsed laser deposition technique. The thicknessof the films drastically influences the transport properties. Asthe thickness decreases, the CO transition becomes more favouredwhile at the same time the insulator-to-metal transition temperaturebecomes less favoured under application of a 7 T magnetic field. Clearrelationships between the structural distortions and thetransport properties are established. They are explained on thebasis of the elongation and the compression of the Mn-O-Mn andMn-O bond angles and distances of the Pnma structure,which modify the bandwidth and the Jahn-Teller distortion inthese materials.