Thermopower Monitoring of Relaxation and Devitrification in Fe-Based Glassy Alloys

The change of thermopower is investigated in Fe-based glassy alloys during structural relaxation and amorphous-crystalline transformation. It was found, that thermopower shifts to negative direction until solely the relaxation proceeds. This negative shift is composition independent. The net shape of thermopower curves is composed from the thermopower of the individual constituent crystalline phases after the crystallization process

Magnetic and structural characterization of NiXSb (X = Mn, Cr) Heusler ribbon

Half-Heusler alloys with composition NiMnSb and NiCrSb have been prepared by rapid-quenching method. NiMnSb half-Heusler alloy is characterized by single phase C1_{b} with polycrystalline structure while crystalline structure of NiCrSb shows multiphase system. Magnetic measurements indicated high anisotropy and easy magnetization direction in the parallel direction with respect to ribbon axis for NiMnSb alloy while paramagnetic behavior appears for NiCrSb alloy down to 50 K

Reversible structural transition in monocrystalline Ni2FeGaNi_{2}FeGa microwires for shape-memory applications

We report on the production and characterization of Heusler-based Ni$_2$FeGa microwires exhibiting two – wayshape memory effect. The microwires are characterized by a monocrystalline structure with a strong preferredcrystallographic orientation that shows [1 1 1] axis parallel to the wire’s axis for high-temperature L2$_1$ austenitephase, while the [0 1 7] axis is preferred for low-temperature monoclinic phase. Variation of crystallographicaxis (and corresponding easy magnetization axis) leads to 1600% variation of magnetic permeability due to a 2%strain in axial direction. Such straining is reversible immediately after production without the necessity of furtherthermal treatment. These properties give the microwire function of very sensitive SMART actuators that can beeasily produced in a large amount

Structural and Magnetic Characterization of NiMnSb Half-Heusler Alloy Prepared by Rapid Quenching

NiMnSb half-Heusler alloy in the form of a rod has been prepared by rapid quenching (suction-casting) method. The rod is characterized by single phase $C1_b$ crystalline structure with lattice parameter a=5.982 Å. Magnetic measurements reveal an isotropic character of bulk NiMnSb alloy. Our study shows relatively high spin polarization of bulk NiMnSb in the range 35-50%