Magnetism and Magnetic Materials

Biography

Biography: Rafał Michalski

Abstract

We present the results of calculations of magnetic properties of three compounds from Laves phase C15 family: DyAl₂, HoAl₂ and ErAl₂ performed with a new computation system called atomic matters MFA. We compare these results with the recently published results for TbAl₂, GdAl₂ and SmAl₂. The calculation methodology was based on the localized electron approach applied to describe the thermal evolution electronic structure of rare-earth R³⁺ ions over a wide temperature range and to compute magnetocaloric effect (MCE). Thermomagnetic properties were calculated based on the fine electronic structure of 4f⁹, 4f¹⁰ and 4f¹¹ configurations of the Dy³⁺, Ho³⁺, Er³⁺ ions, respectively. Our calculations yield the magnetic moment value and direction; single-crystalline magnetization curves in zero field and external magnetic field applied in various directions of m(T, B_ext); the 4f-electronic components of specific heat c_4f(T, B_ext); and temperature dependence of the magnetic entropy and isothermal entropy change with external magnetic field -S(T, B_ext). The cubic CEF parameter values used for DyAl₂ calculations are taken from earlier research of A.L. Lima, A.O. Tsokol and recalculated for universal cubic parameters (A^m_n) for the RAl₂ series. Our studies reveal the importance of multipolar charge interactions when describing thermomagnetic properties of real 4f electronic systems and the effectiveness of an applied self-consistent molecular field in calculations for magnetic phase transition simulation.