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)].

This paper reports an investigation of the gas-sensitive properties of thin film sensors based on the double-layers Fe 2 O 3 -In 2 O 3 and Fe 2 O 3 -In 2 O 3 /In 2 O 3 towards gases of different chemical nature (C 2 H 5 OH, CH 4 , CO, NH 3 , NO 2 , O 3 ). As it was found, the g-Fe 2 O 3 -In 2 O 3 composite (Fe:In ¼ 9:1, mol) is more sensitive to O 3 ; on the contrary, the a-Fe 2 O 3 -In 2 O 3 (9:1) system, possesses a higher sensitivity to NO 2 . The optimal temperature for detecting of both gases is in the range of 70-100 8C. Sensors based on the g-Fe 2 O 3 -In 2 O 3 heterostructure show the maximum response to C 2 H 5 OH at considerably higher temperatures (250-300 8C), but this layer is practically insensitive to other reducing gases like CH 4 , CO and NH 3 in the same temperature range.An explanation of the different gas-sensitive behavior for the these samples resulted from the particular features of their structure and phase state.

Depth selectivity of Mössbauer total external reflection (TER) is demonstrated. A series of CEMS spectra at different glancing angles of an evaporated 20 nm 57Fe film on glass substrate are obtained. A theory of propagation of the radiation in the multilayer medium under TER conditions is used for the interpretation of the results taking into account multiple reflections in each layer. The computer fit gives the three step depth profiles of the distribution of different hyperfine interactions in the film.

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