The magnetization value and electric resistivity of the single-crystalline sample of NiFeCoGa shape memory alloy were measured. The elastic modulus was determined by the Dynamic Mechanical Analysis (DMA). The characteristic temperatures of martensitic transformation (MT) of the alloy were estimated from the temperature dependences of magnetization, electric resistivity and elastic modulus.
View Article and Find Full Text PDFNi-Mn-Ga single crystals (SC) exhibiting a giant magnetic field induced strain (MFIS), resulting from twin boundaries rearrangements, are excellent materials for novel actuators although enhanced brittleness and high costs are remaining the issues for applications. In polycrystalline state Ni-Mn-Ga alloys show small MFIS due to grain boundary constraints. By simple size reduction of the mentioned materials it is hardly possible to create quasi-two-dimensional MFIS actuators on the microscale with a pertinent out-of-plane performance.
View Article and Find Full Text PDFMetamagnetic off-stoichiometric Heusler alloys are actively being investigated because of their great potential as magnetocaloric materials. These properties are intimately related to the nanoscale homogeneity of their magnetic properties, mainly due to a strong influence of the nature of the exchange interactions between Mn atoms on the magnetism of the alloys. In this work, a spontaneous exchange bias phenomenon on a Ni-Co-Mn-Sn metamagnetic Heusler sputtered film is presented and studied in detail.
View Article and Find Full Text PDFRecent advances in the field of magnetic materials emphasize that the development of new and useful magnetic nanoparticles (NPs) requires an accurate and fundamental understanding of their collective magnetic behavior. Studies show that the magnetic properties are strongly affected by the magnetic anisotropy of NPs and by interparticle interactions that are the result of the collective magnetic behavior of NPs. Here we study these effects in more detail.
View Article and Find Full Text PDF