Magnetic structure of a geometrically frustrated garnet Mn₃V₂Ge₃O₁₂.

Sagar Mal Kumawat¹, Tsai-Ling Liu^1*, Chin-Wei Wang², Jia-Xiang Hsu¹, En-Pei Liu³, Wei-Tin Chen^3,4,5, Chien-Lung Huang¹

¹Department of Physics, National Cheng Kung University and Center for Quantum Frontiers of Research & Technology, Tainan, Taiwan
²National Synchrotron Radiation Research Center, (NSRRC), Hsinchu, Taiwan
³Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
⁴Center of Atomic Initiative for New Materials, National Taiwan University, Taipei, Taiwan
⁵Taiwan Consortium of Emergent Crystalline Materials, National Science and Technology Council, Taipei, Taiwan

* Presenter:Tsai-Ling Liu, email:0106.tll@gmail.com

We have synthesized a new garnet oxide, Mn3V2Ge3O12 (MVGO), and investigated its low-temperature magnetic and thermodynamic properties. Room-temperature neutron powder diffraction (NPD) confirmed that MVGO crystallizes in a cubic structure with the space group of Ia-3d, along with a small amount of MnV2O4 spinal oxide impurity phase. Magnetic susceptibility measurements showed two antiferromagnetic transitions around 4 K (TN1) and 2.6 K (TN2). Specific heat measurements confirmed the findings from the magnetic susceptibility, with magnetic entropy from specific heat amounting to approximately 76 % of the theoretical value. Neutron powder diffraction analysis confirmed that the 4 K transition is due to Mn2+ ordering, while the 2.6 K transition involves both Mn2+ and V3+ ordering.

Keywords: geometrically frustrated, garnet oxide, magnetic structure