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Re-entrant spin reorientation transition and Griffiths-like phase in antiferromagnetic TbFe0.5Cr0.5 O3

Mali, B and Nair, HS and Heitmann, TW and Nhalil, H and Antonio, D and Gofryk, K and Bhandari, SR and Ghimire, MP and Elizabeth, S (2020) Re-entrant spin reorientation transition and Griffiths-like phase in antiferromagnetic TbFe0.5Cr0.5 O3. In: Physical Review B, 102 (1).

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Official URL: https://doi.org/10.1103/PhysRevB.102.014418


The perovskite TbFe0.5Cr0.5O3 shows two anomalies in its magnetic susceptibility at TN=257 K and TSR=190 K which are, respectively, the antiferromagnetic and spin-reorientation transition that occur in the Fe/Cr sublattice. Magnetic susceptibility of this compound reveals canonical signatures of a Griffiths-like phase: a negative deviation from the ideal Curie-Weiss law and in less-than-unity power-law susceptibility exponents. Neutron-diffraction data analysis confirms two spin-reorientation transitions in this compound. The first one from �2 (Cx, Gy, Fz) to �4 (Ax, Fy, Gz) occurs at TN=257 K and a second one from �4 (Ax, Fy, Gz) to �2 (Cx, Gy, Fz) at TSR=190 K in the Pnma space-group setting. The �2 (Cx, Gy, Fz) structure is stable down to 7.7 K, leading to an ordered moment of 3.34(1) μB/Fe3+(Cr3+). In addition to the long-range magnetic order, experimental indication of diffuse magnetism is observed in neutron-diffraction data at 7.7 K. Tb develops a ferromagnetic component along the z axis at 20 K. Thermal conductivity and spin-phonon coupling of TbFe0.5Cr0.5O3 studied through Raman spectroscopy are also presented in the paper. The magnetic anomalies at TN and TSR do not appear in the thermal conductivity of TbFe0.5Cr0.5O3, which appears to be robust up to 9 T. On the other hand, they are revealed in the temperature dependence of full-width-at-half-maximum curves derived from Raman intensities. An antiferromagnetic structure with ���� arrangement of Fe/Cr spins is found as the ground state through first-principles energy calculations, supporting the experimentally determined magnetic structure at 7.7 K. The spin-resolved total and partial density of states show that TbFe0.5Cr0.5O3 is insulating with a band gap of �0.12 (2.4) eV within GGA (GGA+U) functionals. © 2020 American Physical Society.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: Copyright of this article belongs to American Physical Society
Keywords: Antiferromagnetism; Calculations; Energy gap; Ground state; Magnetic susceptibility; Neutron diffraction; Perovskite; Temperature distribution; Ternary alloys; Ultrathin films, Antiferromagnetic structures; Ferromagnetic component; Long range magnetic order; Neutron diffraction data; Partial density of state; Spin reorientation transitions; Spin-phonon coupling; Temperature dependence, Thermal conductivity
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 07 Apr 2021 09:52
Last Modified: 07 Apr 2021 09:52
URI: http://eprints.iisc.ac.in/id/eprint/66261

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