A5090847355- Magnetic and transport properties of perovskites and related materials
- Shape Memory Alloy Transformations
- Magnetic Properties and Applications
- Multiferroics and related materials
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- Heusler alloys: electronic and magnetic properties
- Ferroelectric and Piezoelectric Materials
- Rare-earth and actinide compounds
- Physics of Superconductivity and Magnetism
- Thermal Expansion and Ionic Conductivity
- Transition Metal Oxide Nanomaterials
- Topological Materials and Phenomena
- Magnetic Properties of Alloys
- Creativity in Education and Neuroscience
Max Planck Institute for Chemical Physics of Solids
2017-2020
Helmholtz-Zentrum Dresden-Rossendorf
2015-2020
TU Dresden
2015-2017
The magnetocaloric effect of gadolinium has been measured directly in pulsed magnetic fields up to $62\phantom{\rule{0.16em}{0ex}}\mathrm{T}$. maximum observed adiabatic temperature change is $\mathrm{\ensuremath{\Delta}}{T}_{\mathrm{ad}}=60.5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, the initial ${T}_{0}$ being just above $300\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. field dependence $\mathrm{\ensuremath{\Delta}}{T}_{\mathrm{ad}}$ found follow usual ${H}^{2/3}$ law, with a small correction...
We have studied the magnetocaloric effect (MCE) in shape-memory Heusler alloy Ni50Mn35In15 by direct measurements pulsed magnetic fields up to 6 and 20 T. The results T are compared with data obtained from heat-capacity experiments. find a saturation of inverse MCE, related first-order martensitic transition, maximum adiabatic temperature change ΔTad = −7 K at 250 conventional field-dependent MCE near second-order ferromagnetic transition austenitic phase. field allow for an analysis...
Solid-state magnetic refrigeration could disrupt conventional technology based on gas compressors, but affordable materials with large magnetocaloric response are needed. Using direct measurements of adiabatic temperature change in three different regimes magnetic-field sweep rate, the authors investigate dynamics martensitic transition a class Heusler alloys. Here phase-boundary motion is not an issue, speed nucleation can be limiting factor at high rates. For everyday devices working...
To bring magnetic refrigeration to market, superior magnetocaloric materials are still needed. In particular, it is important tune alloy composition promote abrupt, second-order phase transitions, for suitable cooling performance in a field that can vary as rapidly 1000 T/s real device. Studying candidate quaternary alloys very high pulsed fields, the authors find magnetoelastic coupling determines order of transition, and both candidates offer large response, which promises good under...
The present pulsed high-magnetic-field study on Ni50Mn35In15 gives an extra insight into the thermodynamics of martensitic transformation in Heusler shape-memory alloys. transformation-entropy change, ΔS, was estimated from field-dependent magnetization experiments high magnetic fields and by heat-capacity measurements static fields. We found a decrease ΔS with decreasing temperature. This behavior can be understood considering different signs lattice contributions to total entropy. Our...
We report an improved reversibility of magnetostriction and inverse magnetocaloric effect (MCE) for the magnetic shape-memory Heusler alloy ${\mathrm{Ni}}_{1.8}{\mathrm{Mn}}_{1.8}{\mathrm{In}}_{0.4}$. show that MCE crucially depends on geometrical compatibility austenite martensite phases. Detailed information both phases has been obtained from transformation matrix calculated x-ray diffraction data. The uniqueness lattice parameters results in MCE. In thermal hysteresis region martensitic...
Abstract The premartensite phase of shape memory and magnetic alloys (MSMAs) is believed to be a precursor state the martensite with preserved austenite symmetry. thermodynamic stability its relation martensitic still an unresolved issue, even though it critical understanding functional properties MSMAs. We present here unambiguous evidence for macroscopic symmetry breaking leading robust Bain distortion in 10% Pt-substituted Ni 2 MnGa. show that Bain-distorted (T2) results from another (T1)...
We study the dependence of magnetocaloric effect on magnetic field-change-rate first order magnetostructural transition in Mn3GaC by measuring adiabatic temperature change ΔT at three different time scales: 11 mT s−1, 700 and ∼1000 T s−1. find that maximum temperature-change about 5 K is reached s−1 rates, whereas for s−1-rate lags field so not attained.
The magnetocrystalline anisotropy (MAE) of ${\mathrm{Ni}}_{2\ensuremath{-}x}{\mathrm{Pt}}_{x}\mathrm{MnGa}(0\ensuremath{\le}x\ensuremath{\le}0.25)$ alloys are investigated using the singular point detection technique and density functional theory. A slight reduction in MAE as compared to that ${\mathrm{Ni}}_{2}\mathrm{MnGa}$ is observed due Pt substitution. calculated varies almost linearly with orbital moment anisotropy. competition between elastic chemical contributions explains trend...
The large magnetocaloric effect (MCE) observed in Ni-Mn based shape memory Heusler alloys put them forward to use magnetic refrigeration technology. It is associated with a first-order magnetostructural (martensitic) phase transition. We conducted comprehensive study of the MCE for off-stoichiometric alloy ${\mathrm{Ni}}_{2.2}{\mathrm{Mn}}_{0.8}\mathrm{Ga}$ vicinity its found reversible under repeated field cycles. behavior can be attributed small thermal hysteresis martensitic Based on...
In the present study, martensitic transformation (MT) and magnetic properties exhibited by Ni-Mn-Sn Heusle-type shape memory alloys (MSMAs) doped with Zn have been investigated experimentally theoretically. The inverse magnetocaloric effect (MCE) in ${\text{Ni}}_{47}{\text{Mn}}_{40}{\text{Sn}}_{13\ensuremath{-}x}{\text{Zn}}_{x}$ (x = 0, 1) was studied direct measurements of adiabatic temperature change, $\mathrm{\ensuremath{\Delta}}{T}_{\text{ad}}$, pulsed fields 5, 10, 20 T. doping alloy...
We report on the pressure evolution of giant anomalous Hall effect (AHE) in chiral antiferromagnet Mn$_3$Ge. The AHE originating from non-vanishing Berry curvature Mn$_3$Ge can be continuously tuned by application hydrostatic pressure. At room temperature, signal changes sign as a function and vanishes completely at $p=1.53$ GPa. Even though conductivity upon increasing pressure, room-temperature saturation value 23 ${\rm \Omega^{-1}cm^{-1}}$ 2.85 GPa is remarkably high comparable to ambient...