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We present studies of structural, magnetic, and electrical properties of Zn1-x-y CdxMnyGeAs2 nanocomposite ferromagnetic semiconductor samples with changeable chemical composition. The presence of MnAs clusters induces the studied alloy room temperature ferromagnetism with the Curie temperature, TC, around 305?K. The chemical composition of the chalcopyrite matrix controls the geometrical parameters of the clusters, inducing different magnetoresistance effects in the crystals. The presence of ferromagnetic clusters in the alloy induces either negative or positive magnetoresistance with different values. The Cd-content allows a change of magnetoresistance sign in our samples from negative (for x ≈ 0.85 ) to positive (for x ≈ 0.12 ). The negative magnetoresistance present in the samples with x≈0.85 is observed at temperatures T<25 ?K with maximum values of about -32% at T = 1.4 ?K and B = 13 T, strongly depending on the Mn content, y. The positive magnetoresistance present in the samples with x ≈ 0.12 is observed with maximum values not exceeding 50% at B = 13?T and T = 4.3 ?K, changing with the Mn content, y. [ABSTRACT FROM AUTHOR]

Magnetic nanocomposites (MNC), in which nanoparticles of ferromagnetic metals are distributed in wide-gap dielectric matrices (Al2O3 or SiO2), are prospective materials for electronics due to their amenability to technological control of the concentration and size of ferromagnetic nanoparticles. Co/Al2O3 and Co/SiO2 MNC layers with Co concentrations below the percolation threshold were deposited on polycor substrates using electron-beam deposition in a vacuum (EB-PVD). Scanning electron microscopy showed the presence of tightly packed Co grains of irregular shape with sizes of 5–50 nm in MNC. Low-temperature measurements of the magnetization for MNC Co/Al2O3 were made in the temperature range 4–300 K and magnetic fields up to 10 kOe. The 'magnetic exchange bias' has been detected, and it increases with a rise in Co concentration. By studying the electrical properties of the MNC Co/Al2O3 and Co/SiO2 in the temperature range of 77–280 K, the Mott type electron transport hopping mechanism was established. We first observed the effect of a giant positive thermoelectric power in a magnetic field in MNC Co/Al2O3 and the effect of a negative magnetothermoelectric power in a Co/SiO2. [ABSTRACT FROM AUTHOR]

In this paper, the crystallographic, magnetic, thermomagnetic, and magnetocaloric properties of the quenched NiMn1−xCrxGe (x = 0.04, 0.18, and 0.25) half-Heusler alloys have been studied by x-ray diffraction, differential scanning calorimetry and magnetization measurements. An influence of partial substitution of Cr for Mn and quenching of the samples on the character of structural and magnetic phase transitions is presented. Quenching of the alloys results in the formation of two phase (orthorhombic and hexagonal) crystal structure. The magnetic properties were investigated by means of magnetization measurements over a wide temperature (5–400 K) and magnetic field (up to 60 kOe) ranges. The experimental data indicate that at quenching and with increasing Cr content the magnetic order changes from antiferromagnetic to ferromagnetic. Hardened compounds exhibit a thermal hysteresis in the vicinity of the magnetic phase transition, what is characteristic for a first-order magnetic phase transition. The magnetic phase transition temperatures are decreased as a result of quenching of the samples. The magnetic entropy changes were calculated using the field dependences of isothermal magnetization in terms of the thermodynamic Maxwell relation. The magnetic entropy changes, |ΔSMmax|, obtained for the hardened alloys with x = 0.25 have the maximum value equal to 23 J/(kg·K) near the magnetic phase transition for a field change of ΔH = 0–60 kOe. [ABSTRACT FROM AUTHOR]

The influence of Ag± ions and Mn non-stoichiometry on the magnetic properties and magnetocaloric effect in the La0.9-xAgxMn1.1O3 compounds has been studied. The Ag± ions content substituting for trivalent lanthanum ions was varied from x=0.05 to 0.3. Magnetic measurements have been performed over a wide temperature (350-5 K) and magnetic field (up to 5 T) ranges. All the manganites studied show the ferromagnetic-like ordering with a first order magnetic phase transition. The magnetic entropy changes were evaluated from the isothermal curves of magnetization versus an applied magnetic field using both the thermodynamic Maxwell relation (MR) and calculation based on the Landau theory of phase transitions. The largest values of the magnetocaloric effect as well as the relative cooling power among the studied manganites are equal to 5.76 J/(kg K) and 185 J/kg, respectively, for La0.7Ag0.2Mn1.1O3 in the magnetic field change of 5 T near the Curie temperature of TC=271 K. A good correlation between the magnetization, colossal magnetoresistance and magnetic entropy changes as a function of Ag concentration in the La0.9-xAgxMn1.1O3 manganites was established. [ABSTRACT FROM AUTHOR]

The Mn 2− x Fe x P 0.5 As 0.5 compounds ( x = 0.7 and 1.0) studied exhibit the magnetic phase transitions, which are accompanied by a magnetic entropy change. For x = 1 the PM–FM transition is of the first order one with a weak (2–3 K) thermal hysteresis in the vicinity of T C = 275 K. The Mn 1.3 Fe 0.7 P 0.5 As 0.5 compound possesses two magnetic transitions: the second-order PM–FM transition at T C = 190 K, followed by the FM–AFM transition at T N = 90 K, leading to normal and inverse magnetocaloric effects, respectively. The maximum values of magnetic entropy change are equal to 17 J kg −1 K −1 in MnFeP 0.5 As 0.5 and 5 J kg −1 K −1 in Mn 1.3 Fe 0.7 P 0.5 As 0.5 for a field change of 5 T. The magnetic entropy changes were calculated using both the isofield magnetization curves versus temperature and the isothermal magnetization curves versus applied magnetic field. The magnetocaloric effect in MnFeAs 0.5 P 0.5 is discussed in the terms of both the thermodynamic Maxwell relation and the Clausius–Clapeyron equation. [ABSTRACT FROM AUTHOR]

We present a detailed study of layered semiconductor InSe doped with Mn. X-ray and neutron diffraction analyses of (In,Mn)Se single crystals show the presence of a main phase as In1-xMnx solid solution, the second antiferromagnetic MnSe phase, and traces of In4Se3. Magnetic measurements reveal ferromagnetic behavior of (In,Mn)Se with the Curie temperature about 800 K. The ferromagnetic cluster model and exchange interaction via 2D electron gas, as the reasons of spontaneous magnetization, are discussed. The dramatic transformation of (In,Mn)Se electron spin resonance (ESR) spectra as a function of temperature is revealed. At the magnetic field perpendicular to crystallographic c axis, a low-field line within the temperature range 70 down to 4.7 K is observed. It shifts to smaller magnetic fields with temperature decrease. Neutron diffraction studies reveal the strong rise for one of the reflection peaks with temperature decrease in the same temperature region where ESR spectra transformation occurs. This peak corresponds to double MnSe interplanar distance in the [111] direction what is a period of its magnetic lattice. Magnetic structure of (In,Mn)Se single crystal is discussed. [ABSTRACT FROM AUTHOR]

Magnetic nanocomposites (MNC), in which nanoparticles of ferromagnetic metals are distributed in wide-gap dielectric matrices (Al2O3 or SiO2), are prospective materials for electronics due to their amenability to technological control of the concentration and size of ferromagnetic nanoparticles. Co/Al2O3 and Co/SiO2 MNC layers with Co concentrations below the percolation threshold were deposited on polycor substrates using electron-beam deposition in a vacuum (EB-PVD). Scanning electron microscopy showed the presence of tightly packed Co grains of irregular shape with sizes of 5–50 nm in MNC. Low-temperature measurements of the magnetization for MNC Co/Al2O3 were made in the temperature range 4–300 K and magnetic fields up to 10 kOe. The 'magnetic exchange bias' has been detected, and it increases with a rise in Co concentration. By studying the electrical properties of the MNC Co/Al2O3 and Co/SiO2 in the temperature range of 77–280 K, the Mott type electron transport hopping mechanism was established. We first observed the effect of a giant positive thermoelectric power in a magnetic field in MNC Co/Al2O3 and the effect of a negative magnetothermoelectric power in a Co/SiO2. [ABSTRACT FROM AUTHOR]

The conversion of metal-organic frameworks (MOFs) into advanced functional materials offers a promising route for producing unique nanomaterials. MOF-derived systems have the potential to overcome the drawbacks of MOFs, such as low electrical conductivity and poor structural stability, which have hindered their real-world applications in certain cases. In this study, laser scribing was used for pyrolysis of a Cu-based MOF ([Cu 4 {1,4-C 6 H 4 (COO) 2 } 3 (4,4'-bipy) 2 ] n ) to synthesize a Cu-CuO@C composite on the surface of a screen-printed electrode (SPE). Scanning electron microscopy, X-ray diffractometry, and Energy-dispersive X-ray spectroscopy were used for the investigation of the morphology and composition of the fabricated electrodes. The electrochemical properties of Cu-CuO@C/SPE were studied by cyclic voltammetry and differential pulse voltammetry. The proposed flexible electrochemical Cu-CuO@C/SPE sensor for the simultaneous detection of hydroquinone and catechol exhibited good sensitivity, broad linear range (1-500 μM), and low limits of detection (0.39 μM for HQ and 0.056 μM for CT).

Stratified mucin-producing intraepithelial lesion (SMILE) is a rare high-grade cervical precancerous lesion designated a variant of adenocarcinoma in situ (AIS) in the WHO classification. We aimed to determine HPV genotypes, immunohistochemical phenotype and mucin presence in SMILE. Between 2010 and 2018, SMILE was diagnosed in 34 out of 6958 (0.5%) cervical biopsies, in 23 patients. Twenty-six tissue samples from twenty-one patients were available for further analysis, including 13 with SMILE alone, 12 with SIL and/or AIS and one with HSIL, AIS and endocervical adenocarcinoma. HPV genotyping was performed using the Seegene Anyplex II HPV 28 assay. Of the 26 samples, a single HPV genotype was identified in the majority of cases ( n = 22), including 12/13 SMILEs associated with SIL/AIS. All but one were high-risk HPV genotypes (23/24; 96.8%). We identified seven different HPV genotypes, the most common being HPV16 ( n = 10; 43.5%), HPV18 ( n = 8, 34.8%) and HPV 31 ( n = 5, 21.7%). All SMILEs showed a strong positive reaction to p16, CK7, CK19 and high Ki67 expression comparable to adjacent HSIL and/or AIS if present. SMILE showed variable mucin presence and p40-positive squamous differentiation suggesting phenotypic diversity in cervical precancerous lesions infected by single HPV.

Three heteroleptic complexes of Co(ii) tri- tert -butoxysilanethiolates have been synthesized with piperidine [Co{SSi(O t Bu) 3 } 2 (ppd) 2 ] 1, piperazine [Co{SSi(O t Bu) 3 } 2 (NH 3 )] 2 (μ-ppz)·2CH 3 CN 2, and N -ethylimidazole [Co{SSi(O t Bu) 3 } 2 (etim) 2 ] 3. The complexes have been characterized by a single-crystal X-ray, revealing their tetrahedral geometry on Co(ii) coordinated by two nitrogen and two sulfur atoms. Complexes 1 and 3 are mononuclear, whereas 2 is binuclear. The spectral properties and thermal properties of 1-3 complexes were established by FTIR spectroscopy for solid samples and TGA. The magnetic properties of complexes 1, 2, and 3 have been investigated by static magnetic measurements and X-band EPR spectroscopy. These studies have shown that 1 and 3, regardless of the similarity in structure of CoN 2 S 2 cores, demonstrate different types of local magnetic anisotropy. Magnetic investigations of 2 reveal the presence of weak antiferromagnetic intra-molecular Co(ii)-Co(ii) interactions that are strongly influenced by the local magnetic anisotropy of individual Co(ii) ions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)