Detailed measurements of the Hall effect in the Ho
0.8
Lu
0.2
B
12
antiferromagnetic compound (Néel temperature
T
N
= 5.75 K) in magnetic fields up to 80 kOe oriented in the (110) plane at ...temperatures of 1.9–6.6 K are performed. It is established with the contribution separation procedure that the anisotropic positive contribution, which is responsible for the double inversion of the sign of the Hall resistance, dominates in the antiferromagnetic state of Ho
0.8
Lu
0.2
B
12
in fields of 30–50 kOe. A sharp decrease in the amplitude of the isotropic negative contribution at the transition to the antiferromagnetic phase is found. The nature of the detected anomalies in the antiferromagnetic metal with dynamic charge stripes and spin-wave component of the magnetic structure is discussed.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The transverse magnetoresistance of Ho
0.8
Lu
0.2
B
12
dodecaboride with a cage glass structure is studied at low (2–10 K) temperatures. It is demonstrated that the isotropic negative ...magnetoresistance in this antiferromagnet is dominant within the broad temperature range near
T
N
≈ K. This contribution to the total magnetoresistance is due to the scattering of charge carriers by nanoclusters formed by Но
3+
ions, and it can be scaled in the ρ =
f
(μ
2
eff
H
2
/
T
2
) representation. It is found that the magnetoresistance anisotropy above (about 15% at 80 kOe) is due to the positive contribution, which achieves maximum values at the magnetic field direction close to
H
║ 001. The anisotropy of the charge carrier scattering is interpreted in terms of the cooperative dynamic Jahn−Teller effect at В12 clusters.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Improved mechanical properties of oxide dispersion strengthened (ODS) steels, the advanced materials for the reactor core, are due to the high density of uniformly distributed nanosized oxide ...inclusions. Transformation of the nanostructure of ODS steels under irradiation determines their stability during operation in the reactor conditions. In this work, three ODS steels are studied: Eurofer ODS, 10Cr ODS, and KP-3 ODS with different alloying systems. In these steels, the chromium content varies from 9 to 14 at %; such alloying elements as V, Ti, Al, W, and Mn are present in different proportions. The effect of irradiation with iron ions up to 3, 6, and 30 dpa at a temperature of 350°C was studied. The radiation-induced changes were analyzed by transmission electron microscopy and atom probe tomography. Although the sizes of oxide inclusions remained almost without change under irradiation, a decrease in their number density was observed in 10Cr ODS and KP-3 ODS steels, while the number density of oxides in Eurofer ODS steel did not change under the irradiation to 30 dpa. On the whole, the strengthening of the ODS steels due to inclusions during the irradiation to 30 dpa at 350°C changed insignificantly, which indicates their radiation resistance and their low propensity for low-temperature radiation strengthening and embrittlement.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The study is devoted to the methodology of simulation experiments for the analysis of radiation damage of structural materials of nuclear power plants by irradiation with heavy ions and subsequent ...analysis with use of the ultramicroscopy and nanoindentation methods. Details of the irradiation experiments in the TIPr accelerator (Institute for Theoretical and Experimental Physics) with ion energy of 101 keV/nucleon are given. Current approaches to the analysis of radiation-induced changes in the structural phase state of samples irradiated with ions with use of transmission electron microscopy and atom probe tomography are demonstrated. Models for the evaluation of radiation hardening based on microscopic changes, as well as the capabilities of the nanoindentation method for direct measurement of the hardening of a specimen layer irradiated by ions, are considered.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Detailed measurements of the Hall effect in the paramagnetic phase of Ho
0.8
Lu
0.2
B
12
antiferromagnet at the magnetic field up to 80 kOe in the temperature range of 1.9–300 K have been performed. ...It has been found that the transition to the cage glass phase (
T
<
T
* ~ 60 K) is accompanied by the appearance of a positive Hall resistance component in addition to that corresponding to the negative Hall effect. The amplitude and angular dependence of the former depend on the magnitude and direction of the applied magnetic field with respect to the crystallographic axes. The revealed anisotropy of the Hall effect in Ho
0.8
Lu
0.2
B
12
is attributed to the interaction of charge carriers with dynamic charge stripes.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Manganese monoarsenide samples have been prepared by the sealed-ampule technique and characterized by X-ray diffraction, differential thermal analysis, and scanning electron microscopy. The ...hexagonal- to-orthorhombic phase transition of MnAs has been studied using differential scanning calorimetry (DSC) and magnetic measurements. The enthalpy and temperature range of the transition have been determined to be Δ
H
=–5.6 J/g and 312.5–319 K, respectively. The enthalpy and temperature range of the transition are influenced by the quality of the samples. The samples containing inclusions of the metastable, orthorhombic phase have a lower enthalpy and broader temperature range of the magnetostructural transformation of manganese monoarsenide. It has been demonstrated that DSC is an effective tool for assessing the quality of MnAs samples. Temperature dependences of specific magnetization and magnetic permeability for MnAs lend support to the DSC results. From these data, the Curie temperature of MnAs has been determined to be 40°C, in good agreement with previously reported data.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
—
We have studied the caloric and magnetic properties of alloys in the MnAs–ZnGeAs
2
eutectic system. The results demonstrate that the heat effect and temperature range of the ...ferromagnetic-to-paramagnetic phase transformation depend on the crystallite size of manganese arsenide. Reducing the crystallite size to ≤60 nm causes the heat effect of the transformation to disappear, significantly changes the temperature range of the magnetic transition, and raises the Curie temperature of the alloy to 351 K.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The evolution of the escape probability of hot and thermalized photoelectrons to vacuum from GaAs(001) with adsorbed layers of cesium and oxygen under the transition from the negative to positive ...effective electron affinity is studied by photoemission quantum yield spectroscopy. A minimum in the dependence of the escape probability of thermalized electrons at zero affinity is observed. The minimum is caused by a photoelectron capture into the two-dimensional subband states in the near-surface band bending region. Lower escape probability values for the cesium deposition, as compared to the oxygen deposition on the GaAs(Cs,O) surface with negative electron affinity, are explained by the photoelectron reflection or scattering at two-dimensional “metallic” Cs clusters.
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•Transition from negative to positive affinity at GaAs(Cs,O) surface is studied.•Photon-enhanced thermionic emission and direct photoemission are measured.•Nonmonotonic electron escape probability versus affinity is observed.•Electron escape probability minimum at zero affinity is explained.•Evidence of electron reflection or scattering at 2D Cs clusters is obtained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Detailed Hall effect measurements were carried out at helium temperatures of 2.1–4.2 K in the magnetically ordered phases of a Ho
0.8
Lu
0.2
B
12
antiferromagnet in a magnetic field of up to 80 kOe ...on single crystals with normal orientations
n
|| 001 and
n
|| 110. Based on the analysis of the angular dependences of the Hall resistance, some new phase transitions in the antiferromagnetic state were found and the anomalies associated with the effects of interaction between dynamic charge stripes and an external magnetic field were revealed.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
