This title appears in the Scientific Report :
2018
Spin reorientation transition about 50 K in HoFeO3 studied by polarised neutron diffraction on POLI
Spin reorientation transition about 50 K in HoFeO3 studied by polarised neutron diffraction on POLI
The onset of electric polarization is observed in HoFeO3 below 210 K [1]. Previous neutron diffraction measurements in zero field indicate that magnetic structure do not change from RT down to about 55 K where a spin reorientation transition from a weak ferromagnetic (WF) AFM structure with μ(Fe) ║...
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Personal Name(s): | Chatterji, T. (First author) |
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Brown, P. J. / Sazonov, Andrew / Thoma, Henrik / Deng, H. / Roth, G. / Hutanu, Vladimir (Corresponding author) | |
Contributing Institute: |
JARA-FIT; JARA-FIT Streumethoden; JCNS-2 JCNS-FRM-II; JCNS-FRM-II |
Imprint: |
2018
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Conference: | Polarised Neutrons for Condensed-Matter Investigations 2018, Abingdon (England), 2018-07-03 - 2018-07-06 |
Document Type: |
Conference Presentation |
Research Program: |
Jülich Centre for Neutron Research (JCNS) FRM II / MLZ Quantum Condensed Matter: Magnetism, Superconductivity Controlling Collective States |
Subject (ZB): | |
Publikationsportal JuSER |
The onset of electric polarization is observed in HoFeO3 below 210 K [1]. Previous neutron diffraction measurements in zero field indicate that magnetic structure do not change from RT down to about 55 K where a spin reorientation transition from a weak ferromagnetic (WF) AFM structure with μ(Fe) ║ [010] and μ(Ho) = 0 (Γ4 symmetry) to μ(Fe) ║ [100] and μ(Ho) ≈ 0 (Γ1 symmetry) occur [2]. Polarized neutron studies [3] have shown that 9 T applied parallel to [001] at 70 K aligns a moment of magnitude ≈ 1 μB which is almost entirely due to Ho whilst leaving the arrangement of Fe moments in the WF1 structure with Γ4 symmetry essentially unchanged. New polarised neutron diffraction setup using novel high-Tc superconductor compact magnet with maximal field up to 2.2 T has been recently implemented on POLI [4]. Using this setup the evolution of the magnetic structure in HoFeO3 with temperature and field in the range 46-70 K and 0.15-2.2 T were studied using two wavelengths of 0.71 Å and 1.15 Å in cooling and heating cycles respectively. The results from POLI are compatible with the previous data. Above 53 K Γ4 WF model with magnetic moments on Fe directed along [010] could be confirmed. Interestingly that in this phase only one WF domain could be identified even by the lowest field. Below 53 K for the lowest field 0.15 T almost equal population of opposing 180◦ domains was found, and it is strongly field dependent. The application of the field also lowers the temperature of the transition, until in 2.2 T it does not occur above 47 K. Significant components of the magnetic moment on Fe along [001] could be identified at the intermediate fields of about 1 T below 53 K, indicating that reorientation transition breaks orthorombic symmetry. The resulting monoclinic phase determined from polarised neutron diffraction is a coherent combination of the Γ1 and Γ4 structures rather than just a mixture of two phases. References:[1] S. Giri et al. (unpublished results) [2] T. Chatterji, M. Meven, and P. J. Brown (2017) AIP Advances 7 045106.[3] T. Chatterji, A. Stunault and P. J. Brown (2017) J. Phys.: Condens. Matter 29 385802.[4] H. Thoma, W. Luberstetter, J. Peters and V. Hutanu (2018) J. Appl. Cryst. 51 17. |