Peculiarities of the electronic transport in half-metallic Co-based Heusler alloys

Electrical, magnetic and galvanomagnetic properties of half-metallic Heusler alloys of Co$_2$YZ (Y = Ti, V, Cr, Mn, Fe, Ni, and Z = Al, Si, Ga, Ge, In, Sn, Sb) were studied in the temperature range 4.2--900 K and in magnetic fields of up to 100 kOe. It was found that varying Y in affects strongly the electric resistivity and its temperature dependence $\rho(T)$, while this effect is not observed upon changing Z. When Y is varied, extrema (maximum or minimum) are observed in $\rho(T)$ near the Curie temperature $T_C$. At $T < T_C$, the $\rho(T)$ behavior can be ascribed to a change in electronic energy spectrum near the Fermi level. The coefficients of the normal and anomalous Hall effect were determined. It was shown that the latter coefficient, $R_S$, is related to the residual resistivity $\rho_0$ by a power law $R_S \sim \rho_0^k/M_S$ with $M_S$ the spontaneous magnetization. The exponent $k$ was found to be 1.8 for Co$_2$FeZ alloys, which is typical for asymmetric scattering mechanisms, and 2.9 for Co$_2$YAl alloys, which indicates an additional contribution to the anomalous Hall effect. The temperature dependence of resistivity at low temperatures is analyzed and discussed in the framework of the two-magnon scattering theory.Comment: Invited Report on the Moscow International Symposium on Magnetism MISM-2017, pdf only, 6 pages, J. Magn. Magn. Mater., in pres

Size effect in the electronic transport of thin films of Bi 2 Se 3

Thin films of a topological insulator (TI) Bi 2 Se 3 of various thicknesses from 20 nm to 75 nm were obtained. The resistivity measurements were carried out according to the conventional 4-contact DC technique. This allows to "separate" the bulk and surface conductivities at different temperatures and magnetic fields. It was suggested that similar effects should be observed in other TIs and systems with inhomogeneous distribution of dc-current on sample cross section. © 2018 The Authors, published by EDP Sciences.This work was partly supported by the state assignment of FASO of Russia (theme “Spin” No. ȺȺȺȺ Ⱥ 4 ), by the RFBR (project No. 17-52-52008), by the Government of the Russian Federation (state contract No. 02.A03.21.0006), and by grant of Russian Ministry of Education and Science No 14.Z50.31.0025

Features of the electroresistivity, magnetic and galvanomagnetic characteristics in Co2MeSi Heusler alloys

The electro- and magneto-transport as well as magnetic properties of Co2MeSi (Me = Ti, V, Cr, Mn, Fe, Co, Ni) Heusler alloys were studied. The electroresistivity was measured from 4.2 to 300 K, the galvanomagnetic properties (magnetoresistivity and Hall effect) were measured at T = 4.2 K in magnetic fields of up to 100 kOe, and the magnetization at T = 4.2 and 300 K in fields of up to 70 kOe. The normal and anomalous Hall coefficients, saturation magnetization, residual resistivity, current carrier concentration, coefficients at linear contributions into the electroresistivity and magnetoresistivity were obtained. It was shown that on the one hand, there is quite clear correlation between the electronic and magnetic characteristics of Heusler alloys studied, and the spin polarization coefficients of current carriers, taken from well know literature data, on the other hand. The obtained results can be used for creation of new materials for spintronics. © 2021 Author(s).The research was carried out within the state assignment of Ministry of Science and Higher Education of the Russian Federation (theme “Spin” No. AAAA-A18-118020290104-2), was supported in part by the Russian Foundation for Basic Research (Projects Nos. 18-02-00739 and 20-32-90065) and by the Government of the Russian Federation (decision No. 211, contract No. 02.A03.21.0006)

Electrical and optical properties of a PtSn 4 single crystal

A topological semimetal PtSn4 single crystal was grown by method of crystallization from a solution in a melt. Then the electrical resistivity and galvanomagnetic properties (magnetoresistivity and the Hall effect) were studied in the temperature range from 4.2 to 80 K and in magnetic fields up to 100 kOe. The optical measurements were carried out at room temperature. The residual resistivity is shown to be low enough and amount to ∼ 0.5 μOhm•cm. The temperature dependence of the electrical resistivity has a metallic type, increasing monotonically with temperature. A sufficiently large magnetoresistance of 750% is observed. The majority carriers are supposed to be holes with a concentration of ∼ 6.8•10 21 cm -3 and mobility of ∼ 1950 cm 2 /Vs at T = 4.2 K as a result of the Hall effect studies. The optical properties of PtSn 4 have features characteristic of "bad" metals. © 2019 Published under licence by IOP Publishing Ltd.This work was partly supported by the state assignment of Russia (theme “Spin” No. АААА-А18-18020290104-2 and theme “Electron” No. АААА-А18-118020190098-5), by the RFBR (project No.17-52-52008) and by the Government of the Russian Federation (state contract No. 02.A03.21.0006)

Magnetic and thermal properties of alloys close in composition to the spin gapless semiconductor Mn2CoAl

The field dependence of magnetization at T = 4.2 K and in magnetic fields of up to 70 kOe, temperature dependences of magnetization (2 K 11 kOe) magnetization is described in the Stoner models with the Rhodes-Wohlfarth parameter pRW = 1.3 for Mn1.99Co0.96Al1.05 and pRW = 2.3 for Mn1.79Co1.25Al0.96. When the composition deviates from the stoichiometric Mn2CoAl, the spontaneous moment decreases slightly, the effective moment, on the contrary, increases. In this case, a negative sign of the temperature-independent component of the paramagnetic susceptibility is observed. The density of states n(EF) at Fermi level and the Debye temperature ΘD of studied alloys have the usual values for 3d-metal alloys. © 2021 Author(s).The research was carried out within the state assignment of Ministry of Science and Higher Education of the Russian Federation (theme “Spin” No. AAAA-A18-118020290104-2), was supported in part by the Russian Foundation for Basic Research (projects Nos. 18-02-00739 and 20-32-90065) and by the Government of the Russian Federation (decision No. 211, contract No. 02.A03.21.0006). The authors would like to thank D. A. Shishkin and P. B. Terentyev for measuring the magnetic properties of alloys at high temperatures

Structure and magnetic properties of the Co2FeAl and Co2NiSi Heusler alloy films

The structural and magnetic properties (field dependences of the magnetization in magnetic fields of up to 6 kOe) of thin-film Co2FeAl, and Co2NiSi Heusler alloys grown by pulsed laser deposition on glass and a single-crystalline Al2O3 R-plane substrate at different growth temperatures (20, 280 and 420 °C) were studied. It was found that the stoichiometric composition of the films depends on the substrate temperature during growth and repeats the composition of the target for films grown at low temperatures. The films deposited on a single crystalline Al2O3 substrate have uniaxial magnetic anisotropy in the plane. © Published under licence by IOP Publishing Ltd.This work was partly supported by the state assignment of Minobrnauki of Russia (themes “Spin” No. АААА-А18-118020290104-2), RFBR grants (Nos. 18-32-00686 and 18-02-00739) and the Government of the Russian Federation (state contract No. 02.A03.21.0006)

Сравнительный анализ кишечной микробиоты при болезни Паркинсона и других неврологических заболеваниях

Currently the role of microbiota in diseases pathogenesis, its therapeutic and diagnostic potential are of the utmost interest for scientists and medical doctors. Parkinson’s disease is neurodegenerative disorder for which microbiota’s dysbiosis was previously shown.The main goal of the study is to compare the colon microbiota composition in case of Parkinson’s disease and other neurological pathologies, including idiopathic familial dystonia, essential tremor, multiple sclerosis, multiple system atrophy in order to determine the intestinal flora landscape specific to Parkinson’s disease.Material and methods. One hundred twenty-six patients, 93 with Parkinson’s disease and 33 with other neurological pathology were examined. For all patients, physical examination and fecal samples collection were performed. Microbiota taxonomic composition was analyzed by sequencing of bacterial 16S rRNA genes followed by bioinformatic and statistical analysis.As a result of the study, significant differences between groups in microbiota composition were found. Gut microbiota of patients with Parkinson’s disease was characterized by increase of Desulfovibrio piger, Lactobacillus mucosae, Yokenella regensburgei, Alistipes indistinctus, Oscillospira capillosus, Clostridium bolteae, Soleaferrea massiliensis, Butyricimonas virosa, Dorea massiliensis, Victivallis vadensis abundances. Patients with other neurological diseases had increased levels of bacteria belonging to Blautia, Intestinibacter, Coprococcus genera and Anoxystipes fissicatena, Fusobacterium periodonticum, Gemmiger formicilis, Papillibacter cinnamivorans, Roseburia faecis, Lachnoclostridium indolis, Clostridium populeti, Clostridium tertium, Roseburia intestinalis, Eubacterium desmolans, Eubacterium cylindroides, Clostridium clariflavum, Eubacterium eligens, Coprococcus eutactus, Intestinibacter bartlettii species in their gut microbiota.Consequently, gut microbiota in case of Parkinson’s disease was different from the microbiota of patients with other neurological diseases, including neuroinflammatory and neurodegenerative disorders, in terms of taxonomic diversity and composition. В настоящее время большой интерес представляет роль микробиоты в патогенезе различных болезней, а также ее диагностический и терапевтический потенциал. Болезнь Паркинсона – нейродегенеративное заболевание, для которого было показано изменение состава кишечной микробиоты в сравнении со здоровым контролем.Цель данного исследования – сравнительная характеристика кишечной микробиоты лиц с болезнью Паркинсона и другими неврологическими заболеваниями, включая идиопатическую семейную дистонию, эссенциальный тремор, рассеянный склероз, множественную системную атрофию для определения микробиотического ландшафта, характерного именно для болезни Паркинсона.Материал и методы. В исследование были включены 93 пациента с диагнозом болезни Паркинсона и 33 пациента с иными неврологическими заболеваниями. Для каждого пациента проведено физикальное обследование и собраны образцы фекалий. Определение состава микробиоты проводилась секвенированием бактериальных генов 16S рРНК с последующим биоинформатическим и статистическим анализом.Результаты. При сравнительном анализе состава микробиоты были найдены значимые различия. Микробиота кишечника лиц с болезнью Паркинсона характеризовалась увеличением содержания бактерий видов Desulfovibrio piger, Lactobacillus mucosae, Yokenella regensburgei, Alistipes indistinctus, Oscillospira capillosus, Clostridium bolteae, Soleaferrea massiliensis, Butyricimonas virosa, Dorea massiliensis, Victivallis vadensis. У лиц с другими неврологическими заболеваниями преобладали бактерии родов Blautia, Intestinibacter, Coprococcus и видов Anoxystipes fissicatena, Fusobacterium periodonticum, Gemmiger formicilis, Papillibacter cinnamivorans, Roseburia faecis, Lachnoclostridium indolis, Clostridium populeti, Clostridium tertium, Roseburia intestinalis, Eubacterium desmolans, Eubacterium cylindroides, Clostridium clariflavum, Eubacterium eligens, Coprococcus eutactus, Intestinibacter bartlettii.Выводы. Микробиота кишечника при болезни Паркинсона отличается по таксономическому разнообразию и бактериальному составу от микробиоты пациентов с другими неврологическими заболеваниями, в том числе нейровоспалительными и нейродегенеративными.

Morphological and commodity value of broiler chickens ‘Smena 7’

We studied the morphological composition of carcass and its anatomical parts of broiler chickens in 28-, 35-, and 42-day-old cross of “Smena 7”. We have estab-lished with the aid of these experiments that highest yield in 42-day-old broilers of is 37.04% of breast, carcass - 19.41%; thigh - 16.39%; shin - 13.51%, and wing - 10.16%. In carcasses contains 72.57% of muscle tissue, bones - 15.36% and with remnants of skin fat - 8.92%. The cost of ongoing anatomical parts of carcasses depends not only on morphological structure of carcasses, but also on the demand of buyers into separate parts

COMPARISON OF REACTOGENICITY AND IMMUNOGENICITY OF LIVE VACCINES AGAINST INFECTIOUS LARYNGOTRACHEITIS

Humoral immune response and ciliary activity of tracheal mucosa of poultry, vaccinated against infectious laryngotracheitis using ciliostatic test, was studied. Regardless of the vaccination route the vaccines decreased the ciliary activity by 5–9 % on Days 3 to 7 post vaccination. Herewith the vaccine ocular application in some chicks induced oneeye serous conjunctivitis, which resolved subsequently. Oral vaccination did not cause any clinical changes. Serological monitoring revealed an earlier and stronger immunity in poultry vaccinated by ocular route. The required seroprotection level in test groups was higher than the minimal value (80%) starting from Day 16 post vaccination. The period of immunity development after oral vaccination correlated with the vaccine dose volume. Moreover the domestic vaccine was highly competitive with foreign vaccines in immunogenicity and reactogenicity