The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 8 2 2019 11 26 Investigation of doping and particle size effect on structural, magnetic and magnetoresistance properties of manganites Investigation of doping and particle size effect on structural, magnetic and magnetoresistance properties of manganites 79 98 712 FA M. Hakimi P. Kameli 0000-0003-4490-0767 H. Salamati M. Eshraghi A. Aezami Journal Article 2019 11 26  In this paper after introduction of manganites, we have studied the effect of particle size and doping on structural, magnetic and magnetoresistance of LSMO manganite samples. The magnetoresistance measurements show that, by decreasing the particle size LFMR increases. Also the results show that the LFMR increases at low doping levels and decreases at high doping levels. The spin dependent tunneling and scattering at the grain boundaries is the origin of increasing the LFMR at low doping levels. Also the substitution of impurity ions at Mn sites and subsequently weaking of double exchange is responsible for decreasing of LFMR at high doping level.  In this paper after introduction of manganites, we have studied the effect of particle size and doping on structural, magnetic and magnetoresistance of LSMO manganite samples. The magnetoresistance measurements show that, by decreasing the particle size LFMR increases. Also the results show that the LFMR increases at low doping levels and decreases at high doping levels. The spin dependent tunneling and scattering at the grain boundaries is the origin of increasing the LFMR at low doping levels. Also the substitution of impurity ions at Mn sites and subsequently weaking of double exchange is responsible for decreasing of LFMR at high doping level. https://ijpr.iut.ac.ir/article_712_19bc916108fc6938f52cb96f7e087941.pdf