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arXiv · 2010.12285

Magnetic and structural properties of Ni-substituted magnetoelectric Co$_4$Nb$_2$O$_9$

Hadi Papi·Virgile Yves Favre·Hossein Ahmadvand·Mojtaba Alaei·Mohammad Khondabi·Denis Sheptyakov·Lukas Keller·Parviz Kameli·Ivica Zivkovic·Henrik M. Rønnow
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Abstract

The magnetic and structural properties of polycrystalline Co$_{4-x}$ Ni$_x$ Nb$_2$ O$_9$ (x=1,2) have been investigated by neutron powder diffraction, magnetization and heat capacity measurements, and density functional theory (DFT) calculations. For x=1, the compound crystallizes in the trigonal P$\bar{3}$c1 space group. Below T$_N$ = 31 K it develops a weakly non-collinear antiferromagnetig structure with magnetic moments in the ab-plane. The compound with x=2 has crystal structure of the orthorhombic Pbcn space group and shows a hard ferrimagnetic behavior below T$_C$ =47 K. For this compound a weakly non-collinear ferrimagnetic structure with two possible configurations in ab plane was derived from ND study. By calculating magnetic anisotropy energy via DFT, the ground-state magnetic configuration was determined for this compound. The heat capacity study in magnetic fields up to 140 kOe provide further information on the magnetic structure of the compounds.

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Hadi Papi, Virgile Yves Favre, Hossein Ahmadvand, Mojtaba Alaei, Mohammad Khondabi, Denis Sheptyakov, Lukas Keller, Parviz Kameli, Ivica Zivkovic, Henrik M. Rønnow. 2020-10-23. Magnetic and structural properties of Ni-substituted magnetoelectric Co$_4$Nb$_2$O$_9$. https://doi.org/10.1103/physrevb.100.134408

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