# Point-contact spectroscopy of single crystal $La_0_._75Sr_0_._2_5MnO_3$ and resistivity due to electron-phonon interaction

Mitra, J and Raychaudhuri, AK and Gayathri, N and Mukovskii, Ya M (2002) Point-contact spectroscopy of single crystal $La_0_._75Sr_0_._2_5MnO_3$ and resistivity due to electron-phonon interaction. In: Physical Review B, 65 (14). pp. 140406-1.

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## Abstract

In this paper we report point-contact spectroscopy (PCS) measurements on single crystals of metallic $La_0_._75Sr_0_._2_5MnO_3$. The electron-phonon coupling function as obtained from the PCS shows large peaks for phonon frequencies $20\hspace{2mm}meV{\leq}\omega\leq100\hspace{2mm}meV$. This leads to a rather large electron-phonon coupling constant $\lambda≃1.2$. We have shown that a sizable fraction of the total resistivity in the temperature range $T{\leq}0.4T_c$ can be of phononic origin and can be explained using the experimentally observed electron-phonon coupling function. As $T{\rightarrow}T_c$, extra contribution to resistivity arising from spins dominate. We find that the magnetoresistance vanishes in the temperature range $T\leq0.4T_c$, where the predominant contribution to \rho arises from phonons. We have also performed PCS in 6 T magnetic field. The resistivity calculated from the spectrum at 6 T does not differ appreciably from that calculated at 0 T. Our experiment has been validated by a similar experiment on a nonmagnetic perovskite oxide system, $Na_0_._9WO_3$.

Item Type: Journal Article Copyright of this article belongs to The American Physical Society. Division of Physical & Mathematical Sciences > Physics 22 Nov 2007 19 Sep 2010 04:29 http://eprints.iisc.ernet.in/id/eprint/7485