Hyperfine magnetic fields and Curie temperature in the Heusler alloy Ni2MnSn at high pressure

Abstract

The ‘‘hyperfine magnetic field’’- Hhpf at the nuclei of the diamagnetic atoms 119Sn was measured in Heusler alloy Ni2MnSn by Mössbauer absorption spectroscopy for pressures up to 10.8 GPa at room temperature. The pressure dependences of HhpfSn does not show hysteresis and can be fitted by a linear function HhpfSn(P)/HhpfSn(0) =1+kH⋅P with the coefficient kH=−0.095±0.015 GPa−1, where HhpfSn(0)=4.60±0.12T. Diamond anvil cells were used to obtain high pressure at room temperature. The Curie temperature (TC) has been measured (up to 5.2 GPa) in the ‘‘toroid’’ high pressure device using thermal ac susceptibility measurements. That pressure dependence was linear with the coefficient dTC/dP=7.44 K/Gpa [TC(0)=341.3 K]. The compressibility of the sample has been measured by means of resistive strain gauges at hydrostatic pressure up to 9 GPa. The equation (V−V0)/V0=−a⋅P+b⋅P2 has been fitted to the experimental data with the coefficients a=8.64⋅10−3 GPa−1, b=1.13⋅10−4 GPa−2. The drop of the HhpfSn in pressure range 0–10.8 GPa can be explained on the basis of the empirical theory developed by Delyagin, Krylov, and Nesterov [JETP 76, 1049(1980)].

Magnetic properties of Mn-rich Ni2MnSn Heusler alloys under pressure

“…In * Corresponding author. agreement with the experiments [4][5][6][7][8][9], T C of Ni 2 MnSn increased with increasing pressure in the pressure region studied.…”

“…Most Mn-based Heusler alloys X 2 MnZ show ferromagnetic properties. The pressure effect on the Curie temperature T C of these Heusler alloys was studied intensively for Cu 2 MnAl, Ni 2 MnZ (Z = Al, Ga, Sn, Sb), Au 2 MnAl, Pd 2 MnZ (Z = Sn, Sb) and Rh 2 MnZ (Z = Sn, Ge) [1][2][3][4][5][6][7][8][9][10][11], in which Mn atoms have a magnetic moment of about 4 B . The strong magnetism of manganese moment of Mn-based Heusler alloys is mainly due to the definite localized moment of well-separated manganese atoms.…”

Comparative Study of Compressibility of Ni2MnX (X=In, Sn, Sb) Heusler Alloys

“…The isothermal compressibility and the Mössbauer high-pressure experiments of Ni 2 MnSn have been performed by Gavriliuk et. [5]. Moreover, increase in the experimental value of T C with pressure in Ni 2 MnSn [5] is well confirmed by ab initio calculations [6].…”

“…[5]. Moreover, increase in the experimental value of T C with pressure in Ni 2 MnSn [5] is well confirmed by ab initio calculations [6]. The present ab initio studies are addressed to cohesive properties of Ni 2 MnX (X = In, Sn, Sb) (equilibrium lattice constant, cohesive energy), the mechanical properties (bulk modulus, its derivative) and to pressure behaviour of magnetic moments.…”

Electronic structure, equilibrium and magnetic properties of Ni2MnGe: Ab initio study

“…We plotted the curve of the reduced atomic volume V/V 0 against the pressure. According to measurements of the isothermal compressibility reported by Gavriliuk et al [22] for Ni 2 MnSn the similar relative decrease of volume is caused by the hydrostatic pressure up to 9 GPa.…”