Regular Article

Structural response to the magnetic pre-ordering in LiFeSi₂O₆

¹ School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
² UGC DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017, India
³ Department of Physics, IISER Bhopal, Bhopal 462066, India

^a e-mail: bindu@iitmandi.ac.in

Received: 27 December 2018
Received in final form: 18 May 2019
Published online: 1 August 2019

Abstract

We investigate the temperature evolution of the structural parameters of potential ferrotoroidic LiFeSi₂O₆ compound across structural and magnetic phase transitions. The structural transition, T_S is ~230 K and the paramagnetic to antiferromagnetic transition, T_N is ~18 K. The lattice parameters exhibit unusual temperature dependence and based on its behaviour, the experimental results can be divided into 3 regions. In region I (300 K to 240 K), the cell parameters are mainly governed by mere thermal effect. As the compound enters region II (below 240 K to 30 K), the lattice parameters show non-linear behaviour. In this region, the exchange pathways that lead to the magnetic interactions within and between the Fe–Fe chains do not show significant response. The region III (below 30 K) is dominated by the magnetic contribution where we observe setting up of both intra and inter-chain magnetic interactions which could be the possible reason for the ferrotorodic behaviour observed in this compound. We believe that the present results will be helpful in understanding the evolution of spin rings that gives rise to net toroidal moment and its consequent properties.