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Nearly single-phase samples of compound TbCo5 + δ (where δ = 0) are obtained and certified in the poly-and monocrystalline state. The latent heat is measured on these samples for the first time in the region of the spin-reorientation phase transition using differential scanning calorimetry. The latent heat of the transition is found to be 1.3 ± 0.2 kJ/kg. The experimental data are compared with the theoretical results obtained in the framework of the single-ion theory ( Q L = 1.1 kJ/kg). It is found that the discrepancy is insignificant to within the experimental error. [ABSTRACT FROM AUTHOR]

In this work we report on the results of investigation of the magnetocaloric effect in Gd100-xYx (x = 0, 5, 10, 15) cold rolled ribbons. It is shown that the magnetocaloric effect exists within a wide temperature interval 258-295 K and is comparable with magnetocaloric effect observed in bulk samples of pure gadolinium. The value of the magnetocaloric effect in the rolled samples is reduced as compared with the bulk samples and strongly depends on the degree of the plastic deformation. Heat treatment procedures can restore the values of the magnetocaloric effect in the cold rolled ribbons up to initial ones. Thus, cold rolling is proposed to be a promising technique for producing thin forms of magnetocaloric materials for heat exchangers of magnetic cooling devices, modifying microstructure of the materials and related magnetic properties. [ABSTRACT FROM AUTHOR]

A method is proposed for calculating the magnetization curves taking into account the domain structure of a sample, which, in contrast to the method developed by Néel and other researches, does not use a number of assumptions of the Néel model; i.e., this method is more universal. It allows numerical calculation of the micromagnetic state of a sample within a unified approach and has no limitations on the type of magnet anisotropy. [ABSTRACT FROM AUTHOR]

We study the dependence of the magnetocaloric effect on the magnetic field-change-rate the first order magnetostructural transition in Mn3GaC by measuring the adiabatic temperature change ΔT at three different time scales: 11mTs-1, 700mTs-1, and ~1000T s-1. We find that the maximum adiabatic temperature-change of about 5K is reached in the 11mTs-1 and 700mTs-1 rates, whereas for the ~1000 T s-1-rate the transition lags the change in the magnetic field so that the maximum adiabatic temperature-change is not attained. [ABSTRACT FROM AUTHOR]

Cobalt ferrite (CFO) is a promising candidate for magnetostrictive applications like actuators or sensors. We have recently shown that uniaxial magnetic anisotropy can be induced in CFO by reactive sintering using spark plasma sintering (SPS), which leads to an improvement of its magnetostrictive properties. However, the origin of the anisotropy and the formation mechanism remain unexplained so far. In this study, different SPS processes have been conducted to determine which parameter is responsible for the induced uniaxial anisotropy. We demonstrate that the magnetic anisotropy arises during the cooling step when done under SPS's uniaxial compression. In addition, we also investigate the fundamental origin of the magnetic anisotropy induced during the SPS process. We show that the polycrystalline anisotropic cobalt ferrite obtained after SPS exhibits no texture. However, the SPS samples turn isotropic after being annealed in air at 400 °C/2 h, as shown by magnetic and magnetostrictive measurements. A change in ionic distribution after the annealing is also observed by Mössbauer spectroscopy. Our findings suggest that the induced magnetic anisotropy results from the ionic distribution of the Co2+ in the CFO's spinel lattice, a mechanism previously observed in magnetic annealed CFO. This study advances the in-depth understanding of the relationship between SPS processing and magnetic properties of cobalt ferrite. [ABSTRACT FROM AUTHOR]

The magnetization of a Ho2Fe17 single crystal has been measured along the principal crystallographic directions in pulsed magnetic fields up to 60 T. Stepwise discontinuities in the magnetization occur at 45 and 55 T along the [120] and [100] directions, respectively. The data allowed us to deduce the molecular field at the Ho site. As a cross check, the molecular field was determined as well from a magnetization measurement when the Ho2Fe17 single crystal was let rotate freely. Both values are in good agreement with each other. [ABSTRACT FROM AUTHOR]

Mn–Al–C is intended to be one of the "gap magnets" with magnetic performance in-between ferrites and Nd-Fe-B. These magnets are based on the metastable ferromagnetic τ -phase with L1 0 structure, which requires well controlled synthesis to prevent the formation of secondary phases, detrimental for magnetic properties. Here, we investigate the formation of τ -phase in Mn–Al–C using Spark Plasma Sintering (SPS) and compare with conventional annealing. The effect of SPS parameters (pressure and electric current) on the phase formation is also studied. Single τ -phase is obtained for annealing 5 min at 500 ∘ C with SPS. In addition, we show that the initial grain size of the ϵ -phase is influencing the τ -phase transformation and fraction at a given annealing condition, independently of the annealing method used. A faster transformation was observed for smaller initial ϵ -grains. The samples obtained by SPS showed comparable magnetic properties with the conventional annealed ones, reaching coercivity of 0.18 T and saturation magnetization of 114 Am 2 /kg in the optimized samples. The similarity in coercivity is related to the microstructure, as we reveal the presence of structure defects like twin boundaries and dislocations in both materials. [ABSTRACT FROM AUTHOR]

The results of magnetization measurements of a Dy3Ni single crystal are presented. A sharp jump of magnetization is observed along a- and c-axis, whereas the magnetization along the b-axis increases gradually. Lack of saturation, strong anisotropy and relatively low values of the magnetic moments observed in magnetic fields up to 35 T are caused by non-collinear magnetic structure that remains even in strong magnetic fields. A magnetic phase diagram with the magnetic field applied along the main crystallographic axes is presented. [Copyright &y& Elsevier]