Influence of magnetic anisotropy on the vortex stability in circular Permalloy nanodots using energy analysis

• Published in: Materials letters Vol. 372; p. 136988
• Main Authors: Praveen, P., Priyanka, B., ESR, Ajith Nix, Kiruthiga Devi, B., Sinha, J., Behera, B.C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2024
• Subjects: Anisotropy; Micromagnetic Simulations; Permalloy; Vortex; Micromagnetic Simulations; Permalloy; Vortex; Anisotropy
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2024.136988

•Mechanism of magnetization reversal investigated in NiFe-nanodots.•This study performed by varying the strength of out-of-plane magnetic anisotropy.•Critical anisotropy value identified to stabilize the magnetic vortex state.•Energy values estimated at nucleation field, annihilation field and remanent states.•Analysis useful in estimating the energy barrier for the magnetization reversal. We thoroughly investigated the stability of vortex magnetization in Permalloy (Py) circular nanodots with and without magnetocrystalline anisotropy using micromagnetic simulations. This study explores a wide-ranging understanding of influence of anisotropy on hysteresis loops, and spin-configurations, and provides a detailed analysis of the energy profile. The ground state vortex configuration considered of size 64 × 20-nm2 Py-nanodot at zero out-of-plane anisotropy had been modulated till the anisotropy 250 kJ/m3. We analyzed different energy terms at nucleation field, annihilation field and remanent states to gain deeper insights into the magnetization reversal mechanism. The energy analysis revealed an interplay between exchange and demagnetization energies, resulting in the stability of vortex up to a critical anisotropy (CK) 170 kJ/m3. Beyond this CK, the vortex destabilizes, switching the magnetization to a single-domain state. Additionally, we estimated the energy barrier involved in single domain to vortex state transformation. These findings provide valuable insights for designing vortex-based magnetic data storage and memory devices.