Phase transitions in the MnAs1-xSbx alloy system

Abstract

Single crystals of a continuous series of MnAs1‐xSbx solid solutions are obtained and their crystal structure and magnetic properties are investigated in the temperature range from 150 to 600 K. It is shown that the crystal structure of MnAs, MnSb, and alloys with a small content of Sb and As, respectively, is characterized by uniaxial diplacements of atoms in the ferromagnetic state. At the temperature of the first order phase transition Tu the displacements in [001], [011], [011] directions become random. A layered magnetic structure with the ordered arrangement of moments in (100) and arbitrary multiples of 60° in the neighbouring layers is proposed. The destruction of the atter to the paramagnetic state occurs with a second order phase transition (at Tc). For single crystals of composition (0.3 ≦ x ≦ 0.8) the static displacements of Mn atoms are disordered, possibly by the structure defects; here the temperature dependence of the magnetization is described by the Brillouin function. From the data obtained a diagram of transformations (phase diagram) for MnAs1‐xSbx single crystals is plotted.

Elastic and magnetic properties of epitaxial MnAs layers on GaAs

“…We note that, although the qualitative features agree, there are considerable differences in the reported data for the temperature dependence of the lattice constants of bulk MnAs. 7,16,25 For the following discussion, we will concentrate on the data from Ref. 16.…”

Effects of Heat Treatment on the Magnetic Phase Transition and Magnetocaloric Properties of Mn<SUB>1+&delta;</SUB>As<SUB>1&minus;<I>x</I></SUB>Sb<I><SUB>x</SUB></I>

“…When T 2 is higher than the solidus line, the sample is partially melted and the magnetic transition becomes broad. This is the case of 10) In our case, free Sb was precipitated in the slowly cooled sample. This is because our cooling rate ($100 K/h) is too fast to realize an equilibrium state during the cooling.…”

Some structural and magnetic properties of Mn1 + ΔAs1−xPx single crystals

“…In contrast, the (039) Bragg reflection of a x = 12 at% P (curve 3) and a x = 6 at% P (curve 4) (type 1) single crystal show two characteristic temperatures T, = 350 K and Tf. = 240 K which suggest slightly different (3) x = 12at% P; I, 11, 111 temperature regimes defined by T p , Tf (I), (4) s = 6 atYo P, (2) . Y = 20 at% P, Fig.…”