1. Large easy-plane anisotropy induced spin reorientation in magnetoelectric materials (Co 4-x Mn x )Nb 2 O 9 .
- Author
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Deng G, Yu Y, Cao Y, Feng Z, Ren W, Cao S, Studer AJ, Hester JR, Kareri Y, Ulrich C, and McIntyre GJ
- Abstract
Neutron powder diffraction experiments were carried out on the magnetoelectric compound series (Co
4-x Mnx )Nb2 O9 (x = 0, 1, 2, 3, 3.5, 3.9, 3.95 and 4) from base temperature to above their Néel temperatures. Their magnetic structures were analysed by using the irreducible representation analysis and Rietveld refinement method. Similar to Co4 Nb2 O9 , the compounds with x ⩽ 3.9 have noncollinear in-plane magnetic structures (Γ6) with magnetic moments lying purely in the ab plane with certain canting angles. Mn4 Nb2 O9 has a collinear antiferromagnetic structure (Γ2) with magnetic moments aligning along the c axis. The compound of x = 3.95 shows two magnetic phases in the magnetization, which was confirmed to have the Γ2 magnetic structure above 60 K and develop a second Γ6 local phase in addition to the main Γ2 phase due to doping. This study indicates 2.5 at% Co2+ doping is sufficient to alter the collinear easy-axis magnetic structure of Mn4 Nb2 O9 into the noncollinear easy-plane magnetic structure, which is attributed to the large easy-plane anisotropy of Co2+ and relative small Ising-like anisotropy of Mn2+ . The doping effects on the Néel temperature and occupancy are also discussed.- Published
- 2019
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