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.
The effect of an external magnetic field with a strength up to 140 kOe on the phase transitions in manganese arsenide single crystals has been investigated. The existence of unstable magnetic and ...crystal structures at temperatures above the Curie temperature
T
C
= 308 K has been established. The displacements of manganese and arsenic atoms during the magnetostructural phase transition and the shift in the temperature of the first-order magnetostructural phase transition in a magnetic field have been determined. It has been shown that the magnetocaloric effect in a magnetic field of 140 kOe near the Curie temperature
T
C
is equal to Δ
T
∼ 13 K. A model of the superparamagnetic state in MnAs above the temperature
T
C
has been proposed using the data on the magnetic properties and structural transformation in the region of the first-order magnetostructural phase transition. It has been demonstrated that, at temperatures close to
T
C
, apart from the contribution to the change in the entropy from the change in the magnetization there is a significant contribution from the transformation of the crystal lattice due to the magnetostructural phase transition.
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.
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.
(MnZn)1 a x Fe x Sb solid solutions with the Cu2Sb structure have been prepared through heterophase reactions. Their stability range is 0 < x less than or equal to 0.2. The magnetic interaction in ...the solid solutions has a ferromagnetic character. The Curie temperature and mass magnetization of the solid solutions have been determined, and the iron dopant has been shown not to participate in magnetic interaction.
The NiAs-type solid solutions based on manganese antimonide Mn1.1Sb with Zn or Cu (up to 10 at % of substituting component) have been studied by 57Fe Mossbauer spectroscopy. It has been shown that ...the replacement of the manganese antimonide by Cu or Zn does not appreciably affect the main Mossbauer parameters in comparison to those of the parent compound. Two different values of hyperfine magnetic field at Fe are present in all the samples and can be attributed to the metal atoms located in MeI and MeII positions. The substitution of Cu or Zn for manganese antimonide leads to the redistribution of the metal atoms between two cation sublattices.
(MnZn)
1 −
x
Fe
x
Sb solid solutions with the Cu
2
Sb structure have been prepared through heterophase reactions. Their stability range is 0 <
x
≤ 0.2. The magnetic interaction in the solid solutions ...has a ferromagnetic character. The Curie temperature and mass magnetization of the solid solutions have been determined, and the iron dopant has been shown not to participate in magnetic interaction.
PDF
