MAGNETIC ORDERING INVESTIGATION IN MN2ALB2 USING NEUTRON DIFFRACTION

The ternary Mn₂AlB₂ belongs to the (TB₂)_nTal ceramics (T = Cr, Fe, Mn) which exhibit promising bulk properties [M. Ade and H. Hillebrecht, Inorganic Chem. 2015] and their magnetic state was predicted to include the magneto-caloric effect (MCE) [L. Ke. et al, Phys. Rev. B]. In the present work, the magnetic state of Mn₂Al¹¹B₂ is investigated using a DC SQUID magnetization and neutron diffraction. The two-fold increase in magnetization, found at ~60 and ~2 K, is shown to be accompanied by both a rapid change in lattice parameters and an increase of the neutron count of the crystallographic reflections. Below 2 K, a ferromagnetic structure, oriented within the orthorhombic a-c plane is found. This finding solves previous controversy surrounding the magnetic ground state of this compound and will contribute to the future design of magnetic properties in these materials.