Reentrant spin reorientation transition and Griffiths-like phase in antiferromagnetic TbFe$_{0.5}$Cr$_{0.5}$O$_3$
| Autor: | Mali, Bhawana, Nair, Harikrishnan S., Heitmann, T. W., Nhalil, Hariharan, Antonio, Daniel, Gofryk, Krzysztof, Bhandari, Shalika Ram, Ghimire, Madhav Prasad, Elizabeth, Suja |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 102, 014418 (2020) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.102.014418 |
| Popis: | The perovskite TbFe$_{0.5}$Cr$_{0.5}$O$_3$ shows two anomalies in the magnetic susceptibility at $T_N$ = 257K and $T_{SR}$ = 190K which are respectively, the antiferromagnetic and spin reorientation transition that occur in the Fe/Cr sublattice. Analysis of the magnetic susceptibility reveals signatures of Griffiths-like phase in this compound. Neutron diffraction analysis confirms that, as the temperature is reduced from 350K, a spin reorientation transition from $\Gamma_2$ (F$_x$, C$_y$, G$_z$) to $\Gamma_4$ (G$_x$, A$_y$, F$_z$) occurs at $T_N$ = 257K and subsequently, a second spin reorientation takes place from $\Gamma_4$ (G$_x$, A$_y$, F$_z$) to $\Gamma_2$ (F$_x$, C$_y$, G$_z$) at $T_{SR}$ = 190K. The $\Gamma_2$ (F$_x$, C$_y$, G$_z$) structure is stable until 7.7K where an ordered moment of 7.74(1)$\mu_\mathrm B$/Fe$^{3+}$(Cr$^{3+}$) is obtained from neutron data refinement. In addition to the long-range order of the magnetic structure, indication of diffuse magnetic scattering at 7.7K is evident, thereby lending support to the Griffiths-like phase observed in susceptibility. At 7.7K, Tb develops a ferromagnetic component along the crystallographic $a$ axis. Thermal conductivity, and spin-phonon coupling of TbFe$_{0.5}$Cr$_{0.5}$O$_3$ through Raman spectroscopy are studied in the present work. An antiferromagnetic structure with ($\uparrow \downarrow \uparrow \downarrow$) arrangement of Fe/Cr spins is found in the ground state through first-principles energy calculations which supports the experimental magnetic structure at 7.7K. The spin-resolved total and partial density of states are determined showing that TbFe$_{0.5}$Cr$_{0.5}$O$_3$ is insulating with a band gap of $\sim 0.12$ (2.4) eV within GGA (GGA+$U$) functionals. Comment: 11 pages, 10 figures |
| Databáze: | arXiv |
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