Magnetic Heusler alloys which undergo a martensitic transition display interesting functional properties. In the present review, we survey magnetocaloric effects of Ni-Mn-based and discuss their relation with magnetic shape-memory superelasticity reported in these materials. We show that all are consequence strong coupling between structure magnetism enables field to rearrange variants as well provide possibility induce transition. These two features respectively controlled by anisotropy...

Structural and magnetic transformations in the Heusler-based system ${\mathrm{Ni}}_{0.50}{\mathrm{Mn}}_{0.50\ensuremath{-}x}{\mathrm{Sn}}_{x}$ are studied by x-ray diffraction, optical microscopy, differential scanning calorimetry, magnetization. The structural of austenitic-martensitic character. austenite state has an $L{2}_{1}$ structure, whereas structures martensite can be $10M$, $14M$, or $L{1}_{0}$ depending on Sn composition. For samples that undergo martensitic below around room...

The magnetic and structural transformations in the Heusler-based system ${\mathrm{Ni}}_{0.50}{\mathrm{Mn}}_{0.50\ensuremath{-}x}{\mathrm{In}}_{x}$ are studied composition range $0.05\ensuremath{\leqslant}x\ensuremath{\leqslant}0.25$. While cubic phase is preserved $0.165\ensuremath{\leqslant}x\ensuremath{\leqslant}0.25$, we find presence of martensitic alloys with $x\ensuremath{\leqslant}0.16$. In a critical $0.15\ensuremath{\leqslant}x\ensuremath{\leqslant}0.16$, coupling both austenitic...

The elastocaloric effect in the vicinity of martensitic transition a Cu-Zn-Al single crystal has been studied by inducing strain or stress measurements. While trajectories show significant differences, entropy change associated with whole transformation ($\ensuremath{\Delta}{S}_{t}$) is coincident both kinds experiments since production small compared to $\ensuremath{\Delta}{S}_{t}$. values agree estimations based on Clausius-Clapeyron equation. possibility using these materials for...

Applying a magnetic field to ferromagnetic Ni$_{50}$Mn$_{34}$In$_{16}$ alloy in the martensitic state induces structural phase transition austenitic state. This is accompanied by strain which recovers on removing giving system magnetically superelastic character. A further property of this that it also shows inverse magnetocaloric effect. The superelasticity and effect Ni-Mn-In their association with first order studied magnetization, strain, neutron diffraction studies under field.

The very sharp first-order phase transition in single-crystal BaTiO3 permits thermal changes to be driven by small electric fields. resulting giant electrocaloric strength could exploited future cooling devices that operate at high frequency.

Recent progress on caloric effects are reviewed. The application of external stimuli such as magnetic field, hydrostatic pressure, uniaxial stress and electric field give rise respectively to magnetocaloric, barocaloric, elastocaloric electrocaloric effects. values the relevant quantities isothermal entropy adiabatic temperature-changes compiled for selected materials. Large these found when material is in vicinity a phase transition. Quite often there coupling between different degrees...

Energy-efficient and environment-friendly elastocaloric refrigeration, which is a promising replacement of the conventional vapor-compression requires extraordinary properties. Hitherto largest effect obtained in small-size films wires prototype NiTi system. Here, we report colossal effect, well exceeding that alloys, class bulk polycrystalline NiMn-based materials designed with criterion simultaneously having large volume change across phase transition good mechanical The reversible...

It has long been stated that there are profound analogies between fracture experiments and earthquakes; however, few works attempt a complete characterization of the parallels these so separate phenomena. We study acoustic emission events produced during compression Vycor (SiO(2)). The Gutenberg-Richter law, modified Omori's law aftershock productivity hold for minimum 5 decades, independent rate, keep stationary all duration experiments. waiting-time distribution fulfills unified scaling...

We report on the elastocaloric effect in a Cu-Zn-Al shape memory alloy. show that both isothermal entropy and adiabatic temperature changes are large reproducible upon field cycling over very broad span of ∼130 K. The combination such results an outstanding refrigerant capacity ∼2300 J/kg.

Abstract Caloric effects are currently under intense study due to the prospect of environment-friendly cooling applications. Most research is centred on large magnetocaloric and electrocaloric effects, but former require magnetic fields that challenging generate economically latter electric can only be applied without breakdown in thin samples. Here we use small changes hydrostatic pressure drive giant inverse barocaloric near ferrielectric phase transition ammonium sulphate. We find...

In ferromagnetic Ni-Mn-based Heusler alloys undergoing martensitic transformations, a sudden drop in the magnetization is observed as temperature decreases through martensitic-transformation ${M}_{s}$. To understand cause of and thereby nature magnetic coupling this region, we carry out neutron-polarization-analysis experiments on two prototypes, ${\text{Ni}}_{50}{\text{Mn}}_{40}{\text{Sb}}_{10}$ ${\text{Ni}}_{50}{\text{Mn}}_{37}{\text{Sn}}_{13}$. We show that vicinity ${M}_{s}$,...

An experimental study of the acoustic emission generated during a martensitic transformation is presented. A statistical analysis amplitude and lifetime large number signals has revealed power-law behavior for both magnitudes. The exponents these distributions have been evaluated and, through independent measurements to dependence, we checked scaling relation between exponents. Our results are discussed in terms current ideas on avalanche dynamics.

We show that the magnetoelastic coupling between magnetization and amplitude of a short wavelength phonon enables existence first order premartensitic transition from bcc to micromodulated phase in ${\mathrm{Ni}}_{2}\mathrm{MnGa}$. Such has been experimentally evidenced by ac susceptibility ultrasonic measurements under an applied magnetic field. A latent heat around 9 J/mol measured using highly sensitive calorimeter. This value is very good agreement with predicted proposed model.

At certain compositions Ni-Mn-X Heusler alloys (X: group IIIA–VA elements) undergo martensitic transformations, and many of them exhibit inverse magnetocaloric effects. In where X is Sn, the isothermal entropy change largest among alloys, particularly in Ni50Mn37Sn13, it reaches a value 20 J kg−1 K−1 for field 5 T. We substitute Ni with Fe Co this alloy, each amounts 1 3 at % to perturb electronic concentration examine resulting changes properties. Increasing both concentrations causes...

We report on calorimetry under applied hydrostatic pressure and magnetic field at the antiferromagnetic (AFM)-ferromagnetic (FM) transition of Fe$_{49}$Rh$_{51}$. Results demonstrate existence a giant barocaloric effect in this alloy, new functional property that adds to magnetocaloric elastocaloric effects previously reported for alloy. All caloric originate from AFM/FM which encompasses changes volume, magnetization entropy. The strong sensitivity temperatures both confers alloy...

We report on measurements of the adiabatic temperature change in inverse magnetocaloric ${\mathrm{Ni}}_{50}{\mathrm{Mn}}_{34}{\mathrm{In}}_{16}$ alloy. It is shown that this alloy heats up with application a magnetic field around Curie point due to conventional effect. In contrast, effect associated martensitic transition results unusual decrease by magnetization. also provide magnetization and specific heat data which enable compare measured changes values indirectly computed from...

We study the influence of elastic anisotropy on nanoscale precursor textures that exist in some shape-memory alloys and show tweed occurs limit high while a nanocluster phase-separated state for values inhibiting formation martensite. These results are consistent with specific heat data, constant measurements, zero-field cooling or field experiments nonstoichiometric NiTi alloys.