Systematic exploration of magnetic mechanism of La3Co29Si4B10 by first principles calculation

Abstract

Rare earth transition metal compounds with intrinsic and high-performance magnetic behaviors have been attractively research topic as a promising permanent magnets material. In particularly, La3Co29Si4B10 is one of typically rare earth ferromagnetism materials with large magnetic moment and high transition temperature. In order to investigate the magnetic origin of sublattice and guide the design of permanent magnet materials with high magnetic moment and high magnetic crystalline anisotropy, we adopt first principles calculations method to investigate the magnetic mechanism of La3Co29Si4B10 combine local coordination environment with density of states. The results show that the magnetic moment mainly comes from the Co atom. According to the different local symmetry and atom hybridization, the Co atoms at different crystal positions can be divided into high spin state with maximum local magnetic moment at 2c position, low spin state with minimum magnetic moment at 8i1 position and medium spin state corresponding moderate magnetic moment size at other positions. Furthermore, the strain-stress of La3Co29Si4B10 will increase the total magnetic moment. Spin orbital coupling calculation indicate that the easy magnetization direction of La3Co29Si4B10 is along in plane with magnetic crystalline anisotropy energy of 0.68 meV/unit cell, which agreement with experimental. Our calculations lay a theoretical foundation for further experimental design of high-performance permanent magnet materials.