Spin reorientation transition and coupled spin-lattice dynamics of Sm0.6Dy0.4FeO3

Azam Ali Khan; Anju Ahlawat; A Sharma; Pratik Deshmukh; M N Singh; Archna Sagdeo; Vasant Sathe; A K Karnal; S Satapathy

doi:10.1088/1361-648X/ab9d4e

Spin reorientation transition and coupled spin-lattice dynamics of Sm_0.6Dy_0.4FeO₃

J Phys Condens Matter. 2020 Jul 8;32(40). doi: 10.1088/1361-648X/ab9d4e.

Authors

Azam Ali Khan^{1

2}, Anju Ahlawat¹, A Sharma³, Pratik Deshmukh^{1

2}, M N Singh⁴, Archna Sagdeo^{2

4}, Vasant Sathe⁵, A K Karnal^{1

2}, S Satapathy^{1

2}

Affiliations

¹ Laser and Functional Materials Division, Raja Ramanna Centre for Advanced Technology, Indore-452013, India.
² Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai-400094, India.
³ Indian Institute of Technology, Bombay, Mumbai 400076, India.
⁴ Synchrotrons Utilization Section, Raja Ramanna Centre for Advanced Technology, Indore 452017, India.
⁵ UGC-DAE Consortium for Scientific Research, Indore Centre, 452017, India.

PMID: 32544889
DOI: 10.1088/1361-648X/ab9d4e

Abstract

In this work, we have presented a solid-solution of Sm_0.6Dy_0.4FeO₃in the form of nano-particles having spin reorientation transition (SRT) at a temperature interval of 220-260 K. The lattice dynamics of Sm_0.6Dy_0.4FeO₃have investigated by temperature-dependent x-ray diffraction and Raman spectroscopy. A negative thermal expansion at low temperatures has observed, which might be due to the interaction between Sm³⁺and Fe³⁺sublattice. Anomalous behavior in lattice parameters, octahedral tilt angle, and bond lengths have observed in the vicinity of SRT, which confirms the existence of magneto-elastic coupling in the system. The strong anomaly has observed in linewidth and phonon frequencies of Raman modes around SRT, which may be related to the spin-phonon coupling in Sm_0.6Dy_0.4FeO₃. The contribution of SRT in lattice change and the presence of spin-phonon coupling can help to understand the correlation between the magnetic and structural properties of orthoferrite.

Keywords: SmFeO3; magneto-elastics coupling; spin reorientation transition; spin–phonon coupling; synchrotron XRD.