Title: Theoretical study of anisotropy in orbital and antiferromagnetic spin orderings in CMR manganites

Authors: Saswati Panda; D.D. Sahoo; G.C. Rout

Addresses: Department of Physics, Trident Academy of Technology, Chandaka Industrial Estate, Bhubaneswar-751024, India ' Department of Physics, Mahanga Puspagiri Mahavidyalaya, Erakana, Podamarai, Cuttack-754206, India ' Condensed Matter Physics Group, Department of Applied Physics and Ballistics, FM University, Balasore-756019, India

Abstract: We report here a tight binding model for doped rare earth manganites consisting of Kubo-Ohata type double exchange (DE) interaction between the e_g and t_2g band electron spins of same site. A Heisenberg type antiferromagnetic spin-spin interaction is considered among the core band electrons. Both nearest and next nearest neighbouring interactions are taken in the Heisenberg coupling and kinetic energy interaction. The presence of DE interaction induces antiferromagnetism (AFM) in e_g band. The Jahn-Teller (JT) distortion leads to anisotropy in the manganite systems. We have considered JT distortion as an extra mechanism. The model Hamiltonian is solved using Zubarev's Green's function technique. The interplay between temperature dependent lattice strain and transverse spin fluctuations is studied. We have studied the in-plane anisotropy observed in the AFM spin fluctuation and its effect on the lattice strain.

Keywords: colossal magneto-resistance; Jahn-Teller effect; electron correlations; orbital ordering; spin ordering; antiferro magnetism; manganites.

DOI: 10.1504/IJNBM.2019.097590

International Journal of Nano and Biomaterials, 2019 Vol.8 No.1, pp.25 - 34

Received: 10 Apr 2017
Accepted: 27 Mar 2018
Published online: 30 Jan 2019 *

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