•The equiatomic MnZnSb compound were prepared.•Its magnetic properties and magnetocaloric effect (MCE) were systematically studied.•A considerable reversible MCE was observed for MnZnSb around its ...own Curie temperature.•The origin of MCE and its potential application in MnZnSb were discussed.•The field dependence of the MCE was described in frames of the thermo-dynamic theory.
The equiatomic intermetallic alloy MnZnSb with a tetragonal Cu2Sb-type crystal structure (space group P4/nmm) was melted in the resistance furnace in the evacuated quartz ampoule. The adiabatic temperature change (ΔTad) and the isothermal variation of the magnetic entropy (ΔSM) of the MnZnSb compound near to the magnetic phase transition were studied. The ΔTad in a magnetic field up to 1.25 T was studied by the direct method. It was found that temperature dependencies of both ΔTad and ΔSM show a sharp peak near room temperature with a maximum at Curie temperature TC = 317 K. It was shown that there is no temperature hysteresis of the ΔTad in MnZnSb, and the maximum of ΔTad when the compound is heated or cooled is detected at the same temperature. The estimated value of ΔTad in a field of 14 T is 4.5 K. It was shown that near the Curie temperature, the field dependence of the maximum of magnetic entropy change is adequately described by the thermodynamic Landau theory for magnetic second-order phase transitions.
An analysis is presented of experimental and theoretical results of the MnFeAsyP1−y (0.15≤y≤0.66) and Mn2−xFexAs0.5P0.5 (0.5≤x≤1.0) systems to identify main traits that underlie the mechanism of ...formation of different antiferromagnetic (AF) phases in the two systems. The discrepancy between the calculated from first principles and experimental values of the magnetic moment in the ferromagnetic phase with cation substitution in the system Mn2−xFexAs0.5P0.5 is due to the appearance of a canted magnetic structure. In this case, the emergence of an AF phase with decreasing iron concentration precedes a significant change in the electronic d-band filling. In the model of the spiral structure in the system of itinerant electrons it is shown that the stabilization of the AF phase with decreasing arsenic concentration, while maintaining the number of d-electrons, is a consequence of changes in the shape of the density of electronic states that occur with a decrease in unit-cell volume.
► Analysis of differences in formation of magnetic states in Mn2−xFexAsyP1−y was done. ► Based on the results of ab initio calculations and model approach. ► In the Mn2−xFexAs0.5P0.5 system a canted structure in 0.6≤x<0.8 area was found.
The MnSb(Zn) and MnSb(Cu) solid solutions with NiAs-type of crystal structure have been obtained. The existence regions of mono-phase solutions have been determined. Zn and Cu can substitute 10% ...atomic for Mn. On the basis of magnetic measurements it was supposed that the Cu or Zn atoms preferable occupy the MeII sites of NiAs-structure if the amount of nonmagnetic substitution not exceed 10% atomic. The preferable occupation of MeII sites by nonmagnetic atom manifests in rising of the Curie temperature of solid solutions relatively unsubstituted alloy.
An analysis is presented of experimental and theoretical results of the MnFeAs(y)P(1-y) (0.15 less than or equal to y greater than or equal to 0.66) and Mn(2-x)Fe(x)As(0.5)P(0.5) (0.5 less than or ...equal to x less than or equal to 1.0) systems to identify main traits that underlie the mechanism of formation of different antiferromagnetic (AF) phases in the two systems. The discrepancy between the calculated from first principles and experimental values of the magnetic moment in the ferromagnetic phase with cation substitution in the system Mn(2-x)Fe(x)As(0.5)P(0.5) is due to the appearance of a canted magnetic structure. In this case, the emergence of an AF phase with decreasing iron concentration precedes a significant change in the electronic d-band filling. In the model of the spiral structure in the system of itinerant electrons it is shown that the stabilization of the AF phase with decreasing arsenic concentration, while maintaining the number of d-electrons, is a consequence of changes in the shape of the density of electronic states that occur with a decrease in unit-cell volume.
The intermetallic compound Mn
2
Sb (tetragonal structure, Cu
2
Sb type) was exposed to high pressures (4 to 8 GPa) and temperatures (up to 2300 K) for 10 min and was shown to phase-separate to Mn
3
...Sb and Mn
1.5
Sb at certain processing temperatures, pressures, and durations.
We have prepared Mn1.1Sb1 ? y Al y (0 < y ? 0.2) and Mn1.1Sb1 ? y Si y (0 < y ? 0.1) solid solutions with the B8 structure, in which the aluminum and silicon atoms substitute for antimony in the ...anion sublattice of manganese antimonide. Magnetic measurements have shown that substitutions within the stability region of the B8 phase have little effect on the mass magnetization and Curie temperature of the material. Mossbauer spectroscopy results confirm the anion nature of the substitutions.
Mn
1.5 −
x
Cu
x
Sb (
x
≤ 0.30) and Mn
1.5 −
x
Zn
x
Sb (
x
≤ 0.10) solid solutions have been prepared using high-pressure high-temperature processing, and their structural and magnetic properties have ...been studied. The results of magnetic and Mössbauer measurements indicate that the interatomic magnetic interactions in the solid solutions are markedly weaker compared to those prepared by direct melting of elemental mixtures.
Mn
2 −
x
Zn
x
Sb (0.6 ≤
x
≤ 1.0) solid solutions are shown to undergo magnetic phase separation (coexistence of two magnetic phases in a structurally homogeneous material) using a combination of ...characterization techniques (magnetometry, X-ray diffraction, neutron diffraction, Mössbauer spectroscopy, and resistivity measurements). A model is presented for the coexistence of two magnetic phases in the two-sublattice ferrimagnet Mn
2
Sb diamagnetically diluted with zinc.
The phase composition and magnetic state of Mn
1 +
x
Sb (0 ≤
x
≤ 1.0) alloys have been determined before and after high-pressure high-temperature processing (
p
= 8 GPa,
T
= 2300 K). Exposure to high ...pressure and temperature is shown to extend the homogeneity range of hexagonal Mn
1 +
x
Sb alloys (sp. gr.
P
6
3
/
mmc
, no. 194) to
x
= 0.5. The alloys with
x
> 0.5 consist of two phases: hexagonal Mn
1 +
x
Sb and cubic Mn
3
Sb (sp. gr.
Pm
3
m
, no. 221). The magnetic state of the alloys containing manganese in excess of the equiatomic composition can be understood in terms of a two sublattice model and ferrimagnetic ordering.
