Ferrimagnetic-antiferromagnetic phase transition inMn2−xCr

Abstract

Self-consistent spin-polarized energy-band calculations have been performed for Mn2Sb for a ferrimagnetic {FI),ferromagnetic (F), and antiferromagnetic (AF) spin alignment. The calculated local moments on the two types of Mn atoms are in agreement with values obtained from neutron diffraction for FI Mn2Sb. A comparison of the band structures of FI, F, and AF Mn2Sb shows characteristic differences in hybridization between the Mn 3d orbitals and Sb Sp orbitals. The covalent interactions between Mn(1) and Mn(2) 3d orbitals are responsible for a strong direct antiferromagnetic exchange within the triple layers Mn(2)-Mn(1)-Mn{2). The exchange between triple layers is attributed to a much weaker indirect exchange via Sb Sp states. We also carried out measurements of the magnetic properties and the electrical transport properties (resistivity, Seebeck effect, Hall effect) of single crystals and polycrystalline samples of Mn2Sb and Mn2 "Cr"Sb (x & 0.2). The Cr-doped samples show a phase transition from an AF to a FI state. This phase transition is associated with strong changes of the electrical transport properties. We have analyzed these changes in terms of the calculated band structures of FI and AF Mn2Sb.

Electronic and Magnetic Properties of Mn₂Sb_1&minus;<i>_x</i>As<i>_x</i> (<I>x</I> = 0,0.5,1)

“…3.1). Note that our DOS are quite similar to those obtained by other researchers, 10,2022) and that the DOS for both the FR and AF1 states are very much alike except for a few details. The most notable feature is that the magnetic moments of Mn(I) and Mn(II) may be regarded as localized (as explained by Küber et al for Mn atoms in some Heusler alloys 23) ).…”

“…35,10,16) This 19) Then, we estimated the value, a min (or V min ), that gives a minimum total energy. Second, we calculated E tot as a function of c/a using V min and the experimental atomic positions, and then we estimated the value, ðc=aÞ min that gives a minimum total energy.…”

Ab initio calculations and synthesis of the off-stoichiometric half-Heusler phase Ni1−xMn1+xSb

“…The end compound Mn 2 Sb, corresponding to all Ni atoms being replaced by Mn, crystallizes in the tetragonal C38 structure ͑Cu 2 Sb-type͒ and is a normal metal. 26,27 If this crystal phase is obtained, the alloy cannot be expected to remain halfmetallic.…”

Study of magnetic anisotropy in Co-doped Mn2Sb

“…The magnetic structure of Mn 2 Sb consist of triple layer like Mn 1 -Mn 2 -Mn 1 arrangement where Mn 1 (2.1 µ B ) and Mn 2 (3.9 µ B ) are two different crystallographic position with antiparallel spin alignment. In the ferrimagnetic state net moment of adjacent triple layers are parallel whereas in AFM state they are anti-parallel [4][5][6][7][8][9]. With the application of magnetic field as well as pressure, T N of doped Mn 2 Sb can be shifted over a wide temperature range.…”