Transport, Magnetic, and Thermal Properties of La0.7Ca0.24Sr0.06MnO3Single Crystal

Tejas M Tank,Ya M Mukovskii,Ashish Bodhaye,Sankar P Sanyal

doi:10.1155/2013/305308

Tejas M Tank, Ya M Mukovskii + Show 2 more

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https://doi.org/10.1155/2013/305308

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Abstract

We report the transport, magnetic, and thermal properties of La0.7Ca0.24Sr0.06MnO3single crystal. It was prepared using floating zone technique used under oxygen pressure of 1 bar with a typical growth rate of 1 mm/hr. The resistivity data shows the metal to insulator transition (M-I) occuring atTMI=290 K along thec-axis and atTMI=280 K along theab-plane. It is observed that theTMIis higher along thec-axis as compared to that in theab-plane, thus indicating that more favorable hoping of electrons is along thec-axis. From bolometric application point of view, the temperature coefficient of resistance (TCR) is found to be ~28% K−1. Theac-susceptibility measurement shows that this material exhibits ferromagnetic to paramagnetic transition temperature (TC) 277 K. Sharp peak around this temperature in heat capacity data indicates the onset of long-range ordering. The entropy change associated with this transition is found to be 2.3 J/mol K.

Highlights

IntroductionThe perovskite structure of ABO3 with A = La, Pr, and Nd and B = Mn, is paramagnetic insulator at all temperatures
The colossal magnetoresistance (CMR) of hole doped manganites RE1−xAxMnO3, with RE = La, Nd, and Pr and A = Ba, Sr, Ca, and Pb, is promising magnetoresistance materials in which the change of resistivity by applying magnetic field is so large that this effect is described as colossal
It has been found that the bond angle and bond length of Mn+3–O−2– Mn+4 play a crucial role in controlling the CMR properties of these manganites as the geometric quantity and the tolerance factor are modified when suitable ions are substituted for La to fill the 3d network of MnO6 octahedra [6]

Summary

Introduction

The perovskite structure of ABO3 with A = La, Pr, and Nd and B = Mn, is paramagnetic insulator at all temperatures When these are doped with divalent ion, their resistivity decreases with formation of Mn+4, which decreases the Jahn-Teller distortion, creates double exchange interactions, and plays a crucial role in the electrical transport and magnetic properties of these oxides [1]. The problem, is that samples used for such studies (typically ceramic, thin films, or single crystal) represent properties of samples but not the compound as such It concerns especially magnetic and electrical characteristics because they are extremely sensitive to the defect structure of samples. The transport, magnetic, and thermal properties of La0.7Ca0.24Sr0.06MnO3 single crystal have been studied

Experimental

Results and Discussion

Conclusion