In this thesis, structural, magnetic, electrical and magnetoresistance properties of thin films have been studied. The LPCMO bulk sample was prepared by solid-state method. Thin films grown on LaAlO 3 (100)(LAO), SrTiO 3 (100)(STO), (LaAlO 3 ) 0.3 (SrAl 0.5 Ta 0.5 O 3 ) 0.7 (LSAT)(100), LSAT(111) and NaGdO 3 (NGO)(100) substrates by pulsed laser deposition technique and the effect of pulse repetition rate, thickness and strain on the thin films was investigated. For LPCMO/LAO and LPCMO/STO pulse repetition rate of 3, 5 and 10 Hz were chosen. Measurements of resistance indicate that there is a dead layer in the LPCMO/LAO sample deposited by pulse repetition rate of 10 Hz. It is found that the in-plane compressive strain in LPCMO/LAO sample favors the ferromagnetic metallic phase by increasing the hopping amplitude between neighboring electrons, leading to the weakening of phase separation. On the other hand, the in plane tensile strain in LPCMO/STO increases the stability of long-range CO phase in a way that films on STO substrate keeps insulting in entire measuring temperature range even under 1 T magnetic field. In second part, the effect of pulse repetition rate of 3 and 10 Hz at LPCMO/LSAT(100) was investigated. Results show that these films are under in-plane tensile strain. Also the resistance increases and saturation magnetization decrease with lowering pulse repetition rate from 10 to 3 Hz. Moreover, RHEED patterns and AFM analyses show that film grown at pulse repetition rate of 3 Hz has layer growth mode. In order to understand the effects of substrate crystal orientation we choosed LSAT(111). The thin film was prepared at pulse repetition rate of 3 Hz and thickness of 20, 50 and 90 nm. Films resistivity is strongly enhanced when increasing film thickness. The large phase separation in resistance versus temperature in vicinity of IMT results in huge AMR of 148% in a film with thickness of 50 nm. In order to understand the effect of anisotropic epitaxial strain on LPCMO thin film, LPCMO films with three thickness of 20, 50 and 90 nm was prepared on NGO(100) substrate. A colossal anisotropic resistivity of 10 7 can be observed for thinner film. Also the LPCMO/NGO show a strip-like behavior which the sharp resistive jumps seen in the R(T) curve.
