Effect of Ca substitution on transport and magnetic properties of double‐layered manganite La_1.2Sr_1.8Mn₂O₇

Abstract

The resistivity, magnetoresistance (MR) and magnetization of double-layered manganite La 1.2 Sr 1.8-x Ca x Mn 2 O 7 (0.0 ≤ x ≤ 0.4) are studied to investigate the effect of substitution of Ca 2+ for Sr 2+ on the transport and magnetic properties. The resistivity data suggest that Ca doping results in the decrease of insulator-tometal transition temperature, T IM . The conduction mechanism above T IM is found to be of Mott variable range hopping type. The highest MR ratios (∆ρ/ρ 0 ) of 73% (H = 1.5 T) and 93% (H = 4 T) are observed for x = 0.3 sample at ~25 K. The variation of MR with temperature and applied magnetic field is discussed. A secondary transition at T * is observed in all the samples, which may be due to the twodimensional short-range ferromagnetic ordering.

Electrical transport and magnetoresistance of double layered CMR manganites R1.2Sr1.8Mn2O7(R = La, Pr, Sm)

“…The decreasing value of N(E F ) with the decrease of the size of lanthanide ion also indicates that the ability to conduct decreases from LSMO to SSMO. The obtained best fit parameters are in good agreement with the previous reports on similar DL manganites [21,[29][30][31][32]36]. All the fitting parameters in Mott 2D and 3D VRH models vary in a similar manner with lanthanide ion and these results suggest the reliability of the performed fittings.…”

“…However, it is interesting to note that in the present DL manganite system, no peak is seen in MR-T plots unlike the resistivity peak observed at T IM in ρ-T plots (Fig. 2) and the MR increases even below T IM , which is a typical characteristic of DL manganites [14,21,32]. The property of exhibiting CMR effect over a wide temperature range suggests potential applications for layered perovskites.…”

“…In case of DL manganites, the conduction at T > T IM has been explained by Matsukawa et al [29], Zhu et al [30] and others [21,31,32] using Mott type VRH while Chatterjee et al [12] and others [33,34] suggested SPH model. Chen et al [35] suggested ES VRH type of conduction in similar DL manganites.…”

“…Earlier, the author reported the results of transport and elastic properties of some DL manganites [18][19][20][21] …”

Synthesis, Characterization and Magnetotransport Behavior of La-Based Double Layered Manganites

“…Although, some good number of attempts have been made to explore the nature of conduction mechanism of these layered mangnaites at T > T IM [13][14][15][16][17][18][19][20], the transport behavior at T SG < T < T IM and T < T SG is still unclear. In this paper, the conduction mechanism of La [16], but this article is mainly focused on the conduction mechanism in the temperature range 4.2-300 K. The samples were formed in single phase with body-centered tetragonal structure. The insulator-to-metal transition temperature is 123 K for LSMO and 70 K for LSCMO.…”