title: Displacive-type ferroelectricity from magnetic correlations within spin-chain.
abstract: Observation of ferroelectricity among non-d(0) systems, which was believed for a long time an unrealistic concept, led to various proposals for the mechanisms to explain the same (i.e. magnetically induced ferroelectricity) during last decade. Here, we provide support for ferroelectricity of a displacive-type possibly involving magnetic ions due to short-range magnetic correlations within a spin-chain, through the demonstration of magnetoelectric coupling in a Haldane spin-chain compound Er2BaNiO5 well above its Néel temperature of (TN = ) 32 K. There is a distinct evidence for electric polarization setting in near 60 K around which there is an evidence for short-range magnetic correlations from other experimental methods. Raman studies also establish a softening of phonon modes in the same temperature (T) range and T-dependent x-ray diffraction (XRD) patterns also reveal lattice parameters anomalies. Density-functional theory based calculations establish a displacive component (similar to d(0)-ness) as the root-cause of ferroelectricity from (magnetic) NiO6 chain, thereby offering a new route to search for similar materials near room temperature to enable applications.
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400005, India.
authors.forename: Tathamay
authors.initials: T
authors.lastname: Basu
authors.affiliation: S. N. Bose National Centre for Basic Sciences, Sector-III, Block-JD, Salt Lake, Kolkata - 700 098, India.
authors.forename: V V Ravi
authors.initials: VV
authors.lastname: Kishore
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400005, India.
authors.forename: Smita
authors.initials: S
authors.lastname: Gohil
authors.affiliation: 1] Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400005, India [2] UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore - 452001, India.
authors.forename: Kiran
authors.initials: K
authors.lastname: Singh
authors.affiliation: School of Basic Sciences, Indian Institute of Technology Bhubaneshwar, Bhubaneshwar-751013, India.
authors.forename: N
authors.initials: N
authors.lastname: Mohapatra
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400005, India.
authors.forename: S
authors.initials: S
authors.lastname: Bhattacharjee
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400005, India.
authors.forename: Babu
authors.initials: B
authors.lastname: Gonde
authors.affiliation: UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore - 452001, India.
authors.forename: N P
authors.initials: NP
authors.lastname: Lalla
authors.affiliation: S. N. Bose National Centre for Basic Sciences, Sector-III, Block-JD, Salt Lake, Kolkata - 700 098, India.
authors.forename: Priya
authors.initials: P
authors.lastname: Mahadevan
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400005, India.
authors.forename: Shankar
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400005, India.
authors.forename: E V
authors.initials: EV
authors.lastname: Sampathkumaran