Abstract
We present thermodynamic and spectroscopic measurements for an orthopyroxene CoGeO3 with magnetic Co2+ ions that form quasi-one-dimensional ladders. We show that noncollinear magnetic order below TN = 32 K can be stabilized by a strong local easy-axis anisotropy of jeff = 1/2 moments, which is induced by ligand octahedra distortions. Extraction of a magnetic Hamiltonian from inelastic neutron scattering measurements supports this interpretation and allows us to establish an effective magnetic model. The resulting exchange Hamiltonian justifies CoGeO3 as a realization of an Ising spin ladder compound.
| Original language | English |
|---|---|
| Article number | L220407 |
| Pages (from-to) | 1-7 |
| Number of pages | 7 |
| Journal | Physical Review B |
| Volume | 112 |
| Issue number | 22 |
| DOIs | |
| State | Published - Dec 10 2025 |
Funding
Acknowledgments. S.S. thanks Lun Jin and Robert Cava for various stimulating discussions concerning pyroxenes. The authors thank Jong Keum for assistance with x-ray measurements. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by Oak Ridge National Laboratory. The beam time was allocated to CNCS and SEQUOIA spectrometers on Proposals No. IPTS-31133 and No. IPTS-31247, respectively. Heat capacity and magnetization data collection and analysis were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division (M.S.C., M.A.M.). X-ray measurements were performed at the Center for Nanophase Materials Sciences (CNMS) at ORNL, which is a DOE Office of Science User Facility. Calculations of the spin-wave spectrum were supported by Russian Science foundation (Project No. RSF 23-12-00159). The analysis of the phase diagram is supported by the Ministry of Science and Higher Education of the Russian Federation through funding the Institute of Metal Physics. S.S. thanks Lun Jin and Robert Cava for various stimulating discussions concerning pyroxenes. The authors thank Jong Keum for assistance with x-ray measurements. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by Oak Ridge National Laboratory. The beam time was allocated to CNCS and SEQUOIA spectrometers on Proposals No. IPTS-31133 and No. IPTS-31247, respectively. Heat capacity and magnetization data collection and analysis were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division (M.S.C., M.A.M.). X-ray measurements were performed at the Center for Nanophase Materials Sciences (CNMS) at ORNL, which is a DOE Office of Science User Facility. Calculations of the spin-wave spectrum were supported by Russian Science foundation (Project No. RSF 23-12-00159). The analysis of the phase diagram is supported by the Ministry of Science and Higher Education of the Russian Federation through funding the Institute of Metal Physics.