The Origin of the Magnetic and Electric Dipole Moments of Ni²⁺ in NiCr₂O₄

• Published in: Condensed Matter
• Main Authors: Mikhail Eremin, Kirill Vasin
• Format: Article
• Language: English
• Published: MDPI AG 2023-02-01
• Subjects: magnetodielectric effect; spin–orbit coupling; crystal field
• Online Access: https://www.mdpi.com/2410-3896/8/1/23

The energy level schema of the ground term of the nickel ion in NiCr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula>O<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula> was calculated. The parameters of the interaction with the electric field were determined, and the distribution pattern of the electric dipole moments over different positions of nickel in the unit cell was calculated. The model of the NiCr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula>O<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula> magnetoelectric structure at T < T<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mi>c</mi></msub></semantics></math></inline-formula> was constructed taking into account the data on neutron scattering and the results of the electric polarization measurements. The origin of the magnetodielectric effect was attributed to the peculiarities of the ground state of the nickel ion.