Regensburg 2019 – scientific programme

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MA: Fachverband Magnetismus

MA 23: Soft and hard permanent bulk magnets

MA 23.5: Talk

Tuesday, April 2, 2019, 15:00–15:15, H53

A multiscale study of antiphase boundary of the MnAl τ-phase — •Sergiu Arapan¹, Pablo Nieves², and Thomas Schrefl³ — ¹IT4Innovations, VSB-Technical University of Ostrava, 17. listopadu 15, CZ-70833 Ostrava-Poruba, Czech Republic — ²ICCRAM, International Research Center in Critical Raw Materials and Advanced Industrial Technologies, University of Burgos, 09001 Burgos, Spain — ³Department for Integrated Sensor Systems, Danube University Krems, 2700 Wiener Neustadt, Austria

We have implemented a multiscale model to design a realistic permanent magnet material. We quantify for the first time the exchange interaction strength across the antiphase boundary (APB) defect of the MnAl τ-phase with a simple approach derived from first-principles. The calculated exchange interaction at the APB of the MnAl τ-phase is strong enough to form an APB decorated with a domain wall, as it is always observed in experiments. This result is used in micromagnetic simulations for designing a microstructure of the MnAl τ-phase with APBs that optimizes the energy density product. The link between first-principle and micromagnetic calculations is porvided by atomistic spin dynamics. The developed multiscale modelling shows that ABPs deteriorate the loop shape through nucleation of reversed domains at very low field values and successive domain wall pinning. The energy density product decreases with increasing the number of antiphase boundaries.