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arXiv · 1702.06571

Magnetic Properties of New Triangular Lattice Magnets A${_4}$B'B${_2}$O$_{12}$

Ryan Rawl·Minseong Lee·Eun Sang Choi·Guang Li·Kuan-Wen Chen·Ryan Baumbach·Clarina R. dela Cruz·Jie Ma·Haidong Zhou
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Abstract

The geometrically frustrated two dimensional triangular lattice magnets A${_4}$B'B${_2}$O$_{12}$ (A = Ba, Sr, La; B' = Co, Ni, Mn; B = W, Re) have been studied by x-ray diffraction, AC and DC susceptibilities, powder neutron diffraction, and specific heat measurements. The results reveal that (i) the samples containing Co$^{2+}$ (effective spin-1/2) and Ni$^{2+}$ (spin-1) ions with small spin numbers exhibit ferromagnetic (FM) ordering while the sample containing Mn$^{2+}$ (spin-5/2) ions with a large spin number exhibits antiferromagnetic (AFM) ordering. We ascribe these spin number manipulated ground states to the competition between the AFM B'-O-O-B' and FM B'-O-B-O-B' superexchange interactions; (ii) the chemical pressure introduced into the Co containing samples through the replacement of different size ions on the A site finely tunes the FM ordering temperature of the system. We attribute this effect to the modification of the FM interaction strength induced by the change of the O-B-O angle through chemical pressure.

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Ryan Rawl, Minseong Lee, Eun Sang Choi, Guang Li, Kuan-Wen Chen, Ryan Baumbach, Clarina R. dela Cruz, Jie Ma, Haidong Zhou. 2017-02-21. Magnetic Properties of New Triangular Lattice Magnets A${_4}$B'B${_2}$O$_{12}$. https://doi.org/10.1103/physrevb.95.174438

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