Seminarium Oddziału Badań Magnetyków
sala nr 6 (bud. II)
Origin of magnetic ordering in EuZn2P2
dr Shovan Dan
Oddział Badań Magnetyków, INTiBS PAN
Recently, EuZn2P2 has been reported as an insulating antiferromagnetic material [ Phys. Rev. B 2022, 106 054420], and the authors tried to explain the origin of magnetism from very classical dipolar interactions. We revisited the compound and performed the electrical transport and magnetic properties.
As the compound is an insulator even at a higher magnetic field, the conventional exchange mechanisms, ( viz ., direct exchange, Ruderman Kittel Kasuya Yosida exchange, Stoner model of band magnetism or the defect induced d 0 magnetism) fail to explain the magnetic ordering that normally argued to be responsible in an intermetallic compound. Thus , we have used a detailed ab initio DFT calculation to estimate the electronic band structure, anisotropic exchange parameters (J J⊥ , J and variation of in planner magnetocrystalline anisotropy energy to correctly correlate the experimental results. We presumed an extended superexchange model to explain the magnetic ordering, assuming phosphorus as anions. The modification in charge and spin density profile, adapted from DFT calculations supports our assumptions and shows an accumulation of electric charge and spin moments around phosphorus atoms, indicating phosphorus atoms as anionic mediators in the superexchange mechanism. To further support our model, we performed a Monte Carlo simulation using the Heisenberg model and the exchange parameters obtained from the DFT calculation. The simulated specific heat as well as the magnetization (using a Eu 2+ spin block of 8×8×16 and 16×16×32) shows a dominati ng AFM ordering at 21 K, with an excellent agreement to the experimental observations.
Ref:
Phys. Rev. B 108(2023)054402
