Nearly compensated ferrimagnetic behaviour and giant exchange bias of hexagonal Mn2PtAl: experimental and theoretical studies

Akhilesh Kumar Patel; S Shanmukharao Samatham; Alexey V Lukoyanov; P D Babu; K G Suresh

doi:10.1039/d2cp02643k

Nearly compensated ferrimagnetic behaviour and giant exchange bias of hexagonal Mn₂PtAl: experimental and theoretical studies

Phys Chem Chem Phys. 2022 Dec 14;24(48):29539-29546. doi: 10.1039/d2cp02643k.

Authors

Akhilesh Kumar Patel^{1

2}, S Shanmukharao Samatham³, Alexey V Lukoyanov^{4

5}, P D Babu⁶, K G Suresh¹

Affiliations

¹ Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology Bombay, Mumbai 400 076, Maharashtra, India.
² Department of Materials Science and Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel.
³ Department of Physics, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad 500 075, India. shanmukharao_physics@cbit.ac.in.
⁴ M. N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia.
⁵ Ural Federal University, 620002, Ekaterinburg, Russia.
⁶ UGC-DAE Consortium for Scientific Research, Mumbai Center, BARC Campus, Mumbai 400085, India.

PMID: 36448471
DOI: 10.1039/d2cp02643k

Abstract

We have investigated the Mn₂PtAl Heulser alloy to unravel its structural, magnetic, calorimetric and electronic structure properties. At room temperature, the alloy crystallizes in a hexagonal structure. Magnetization reveals a weak martensitic transition at 307 K, followed by a long range ferrimagnetic transition at 90 K. Griffiths phase-like signature and positive Weiss temperature in dc-magnetization, isothermal magnetic hysteresis loops and a frequency-independent peak confirm a nearly compensated ferrimagnetic order of Mn₂PtAl. The theoretical electronic structure calculations also reveal the ferrimagnetic ground state of Mn₂PtAl and Mn ions (occupying different sites) with a very small total magnetic moment. A giant exchange bias field of 2.73 kOe, at a temperature of 3 K and a cooling field of 70 kOe, has been estimated and is attributed to the unidirectional anisotropy associated with possible ferromagnetic clusters formed by the field cooling process in the ferrimagnetic matrix.