Suppressing magnetic order in GeNi2O4 and GeCo2O4
Abstract
Spin S = 3/2 GeCo2O4 and spin S = 1 GeNi2O4 are both frustrated spinels, but they nevertheless order magnetically a low temperatures. GeCo2O4 achieves this by undergoing a structural phase transition, but the mechanism adopted by GeNi2O4 is still an open question. We measured the magnetization, specific heat and magnetocaloric effect in polycrystalline samples of the title materials in high fields up to 45 T, and obtained detailed H,T phase diagrams. In the case of GeNi2O4 an almost degenerate double phase transition in zero field splits into two transitions separated by a wide magnetic field gap. The possibility of a spin-flop transition driven by single-ion anisotropy that also relieves the frustration in the Ni compound will be discussed.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2006
- Bibcode:
- 2006APS..MARH20004J