Abstract
Magnetic and electronic transport properties of Bi0.3-xLaxPr0.3Ca0.4Mn0.1Cr0.9O3 (0≤x≤0.2) manganites have been investigated by measurements of AC-susceptibility, resistivity and magnetoresistance. The samples were prepared using conventional solid-state synthesis method. Magnetic susceptibility versus temperature measurements showed all samples exhibit ferromagnetic to paramagnetic transition with Curie temperature, Tc enhanced from 111 K (x=0) to 174 K (x=0.2). Electrical resistivity measurements of the samples in zero field showed increase of metal-insulator (MI) transition temperature from 58 K(x=0) to 88 K(x=0.2). The increase in both Tc and TMI indicates enhancement of double exchange (DE) interaction involving Mn3+ and Mn4+ ions as a result of weakening of the hybridization effect between Bi3+ 6s2 lone pair with O orbital due to La3+ substitution. La substitution in the Bi-based compound is suggested reduce MnO6 octahedral distortion hence increasing delocalization of charge carriers. The observed variation in MR behavior due to La substitution indicates the substitution influence the MR mechanism of extrinsic and intrinsic behavior in Bi0.3-xLaxPr0.3Ca0.4Mn0.1Cr0.9O3 .Â
Highlights
A number of works have been focused on mixed valence manganites of the type Ln1-xDxMnO3, where Ln represents trivalent rare earth ions such as La, Pr, Nd, Eu, Y and D represents alkaline ions such as Ca, Sr, Pb, Ba due to its unique physical properties such as the observation of colossal magnetoresistance effect (CMR) and transition of metal to insulator behavior which simultaneously occur at the same temperature region of ferromagnetic to paramagnetic transition [1,2]
The CMR effect, which is a phenomena related to the change of resistivity attributed to the improvement of charge carrier spin alignment induced by external magnetic field has generated considerable interest due to its potential application such as in spintronic based technologies [1,2]
Other factors such as electron-phonon coupling arising from Jahn-Teller effect [4] have been proposed to play a significant role on the observed variation of physical behavior which indicates that double exchange (DE) alone is not sufficient for a complete explanation of complex physical behaviours of mixed valence manganites
Summary
A number of works have been focused on mixed valence manganites of the type Ln1-xDxMnO3, where Ln represents trivalent rare earth ions such as La, Pr, Nd, Eu , Y and D represents alkaline ions such as Ca, Sr, Pb, Ba due to its unique physical properties such as the observation of colossal magnetoresistance effect (CMR) and transition of metal to insulator behavior which simultaneously occur at the same temperature region of ferromagnetic to paramagnetic transition [1,2]. The observed physical phenomena of metal-insulator transition and the MR effect can be understood by the double exhange (DE) mechansim which involves the interaction between pairs of Mn3+ and Mn4+ ions as proposed by Zener [3]. Other factors such as electron-phonon coupling arising from Jahn-Teller effect [4] have been proposed to play a significant role on the observed variation of physical behavior which indicates that DE alone is not sufficient for a complete explanation of complex physical behaviours of mixed valence manganites. An analysis of the effects of La3+on resistivity data for metallic and insulator regions based on electron-electron and electronmagnon scattering models and the variable-range hopping model, respectively, are presented
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
