Comparative study of magneto-transport and lattice-vibrational properties of La2/3Ca1/3MnO3 thin films grown on SrTiO3 and LaAlO3 substrates

Abstract

Epitaxial La[Formula: see text]Ca[Formula: see text]MnO3 (LCMO) thin films of 60 nm are deposited on (001)-oriented SrTiO3 (STO) and LaAlO3 (LAO) substrate by modified off-axis magnetron sputtering method. The strain state of the films have been studied by high resolution X-ray diffraction. The magneto-transport properties were found to be strongly dependent on the substrate used. Compared with LCMO/LAO film (compressive strain), LCMO/STO film with tensile strain exhibits lower metal-insulator transition temperature, suppressed Curie temperature, higher resistivity and more localization of electron. The evolution of the Raman modes has also been investigated. The vibrational mode of LCMO/LAO is comparable to the bulk, while the signature of vibration mode at about 610 cm[Formula: see text] induced by strain-related distortion has been observed only in tensile strained LCMO/STO case. The controversial 660 cm[Formula: see text] peak is not observed in our films, which precludes the possible existence of Mn3O4 precipitates in the films.