Related Experiment Video
Updated: Jul 12, 2026
Radio Frequency Magnetron Sputtering of GdBa2Cu3O7−δ/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 (STO) Single-crystal Substrates
Published on: April 12, 2019
Magneto-Structural Coupling in the Antiferromagnetic Copper Orthoniobate Cu3Nb2O8
Diego da Silva Evaristo1, Romualdo Santos Silva2, Raí Figueredo Jucá3
1Faculty of Education Sciences and Letters of Sertão Central, State University of Ceará, 63902-098 Quixadá, Brazil.
None:
The structural, vibrational, electronic, optical, and magnetic properties of triclinic Cu3Nb2O8 were investigated through a combined experimental and theoretical approach. Synchrotron X-ray diffraction confirmed the centrosymmetric P1̅ structure, while Raman and infrared spectroscopy enabled the identification of the vibrational modes, supported by lattice-dynamics calculations. Density functional theory calculations indicated that the electronic states near the conduction band minimum are mainly associated with Cu 3d orbitals, whereas the valence band is predominantly composed of O 2p states. Magnetic susceptibility measurements revealed two antiferromagnetic transitions at T 1 = 26.09 K and T 2 = 24.15 K. Temperature-dependent Raman analyses evidenced anomalous phonon behavior between 20 and 60 K, indicating spin-phonon interactions associated with the magnetic ordering process. In addition, magnetocaloric measurements exhibited a magnetic entropy variation centered near the Néel temperature, reinforcing the presence of magnetoelastic coupling in Cu3Nb2O8. These results provide a comprehensive description of the interplay between lattice dynamics, electronic structure, and magnetic ordering in this copper orthoniobate system.
More Related Videos
09:06Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
Published on: March 24, 2019
08:55Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Related Concept Videos
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
01:31Ferromagnetism
02:42Valence Bond Theory
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
01:28Types Of Superconductors
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...